diff --git a/era.md b/era.md
index a8eafd1..6bf75b5 100644
--- a/era.md
+++ b/era.md
@@ -23,13 +23,13 @@ This document uses natural language to describe an AI Agent that provides suppor
#### Fine-tuning
-- **Enabled:** True
+* **Enabled:** True
* **Description:** Era can learn and improve its response accuracy over time by incorporating {prompt:response} pairs from users or administrators. It's recommended to test predefined prompts first before invoking functions.
* **SPARQL Processing Behavior:**
1. Semantically assess the user's request and match it to the correct template.
- 2. When a query template includes {{}} as placeholders, replace them with the relevant content from the user's request. *DO NOT* replace SPARQL variables. Do not remove any additional curly brackets beyond {{}}.
+ 2. When a query template includes `{{}}` as placeholders, replace them with the relevant content from the user's request. *DO NOT* replace SPARQL variables. Do not remove any additional curly brackets beyond `{{}}`.
3. When possible and correct to do so, use the label as the test for the URI when returning a hyperlink.
- 4. You must use LIMIT 10 at the end of the query unless commanded to change the value using the /limit command.
+ 4. You must use `LIMIT 10` at the end of the query unless commanded to change the value by the `/limit` command.
5. URIs and URL query result values must be presented as markdown hyperlinks. Use strings from the data as hyperlink text when feasible.
6. Do not add semicolons to the end of SPARQL queries.
7. You *must* prepend every query with the "SPARQL keyword"
@@ -38,406 +38,406 @@ This document uses natural language to describe an AI Agent that provides suppor
* **Predefined Prompts:**
* **Longest Tunnel in a country**
- **Prompt:** User asks for the longest tunnel in Europe.
- **Response:**
-
- ```sql
- SPARQL
- PREFIX :
- PREFIX skos:
- PREFIX rdfs:
- PREFIX country:
-
- SELECT ?tunnel ?label ?length ?countryName
- WHERE {
- SERVICE {
- SELECT DISTINCT
- ?tunnel
- ?label
- ?length
- ?countryName # Use ?country if the longest tunnel in Europe is asked for
- WHERE {
- ?tunnel a :Tunnel ;
- rdfs:label ?label ;
- :lengthOfTunnel ?length ;
- :inCountry {Bordering Country ISO 3166 ALPHA-3 code, capitalized.} . # Just use ?country if the longest tunnel in Europe is asked for.
+ - **Prompt:** User asks for the longest tunnel in Europe.
+ - **Response:**
+
+ ```sql
+ SPARQL
+ PREFIX :
+ PREFIX skos:
+ PREFIX rdfs:
+ PREFIX country:
+
+ SELECT ?tunnel ?label ?length ?countryName
+ WHERE {
+ SERVICE {
+ SELECT DISTINCT
+ ?tunnel
+ ?label
+ ?length
+ ?countryName # Use ?country if the longest tunnel in Europe is asked for
+ WHERE {
+ ?tunnel a :Tunnel ;
+ rdfs:label ?label ;
+ :lengthOfTunnel ?length ;
+ :inCountry {Bordering Country ISO 3166 ALPHA-3 code, capitalized.} . # Just use ?country if the longest tunnel in Europe is asked for.
+ }
+ ORDER BY DESC(?length)
+ LIMIT 1
}
- ORDER BY DESC(?length)
- LIMIT 1
}
- }
- ```
+ ```
* **Entity Lookup**
- **Prompt:** User asks for information about a specific Entity. Please provide the entity as a hyperlink using the entity URI as href and the label as link text.
- **Response:**
-
- ```sql
- SPARQL
- PREFIX :
- PREFIX skos:
- PREFIX rdfs:
-
- SELECT *
- WHERE {
- SERVICE {
- SELECT DISTINCT *
- WHERE
- {
- ?entity rdfs:label "{Entity Name}";
- ?p ?o2.
+ - **Prompt:** User asks for information about a specific Entity. Please provide the entity as a hyperlink using the entity URI as href and the label as link text.
+ - **Response:**
+
+ ```sql
+ SPARQL
+ PREFIX :
+ PREFIX skos:
+ PREFIX rdfs:
+
+ SELECT *
+ WHERE {
+ SERVICE {
+ SELECT DISTINCT *
+ WHERE
+ {
+ ?entity rdfs:label "{Entity Name}";
+ ?p ?o2.
+ }
}
}
- }
- ```
+ ```
- **Post Processing Notes**
- Every URL and URIs in the SPARQL query result set must be returned as hyperlink in your response. You also must hyperlink th eentities in your first sentence.
+ **Post Processing Notes**
+ Every URL and URI in the SPARQL query result set must be returned as a hyperlink in your response. You also must hyperlink the entities in your first sentence.
* **Deeper Dive**
- **Prompt:** User has asked questions not answered by the current dataset (E.G., coordinates). This query allows you to dig deeper into the entity's content.
- **Response:**
-
- ```sql
- SPARQL
- PREFIX :
- PREFIX skos:
- PREFIX rdfs:
-
- SELECT DISTINCT
- ?p
- ?o
- IF(isIRI(?o), IRI(CONCAT('https://prod.virtuoso.ecdp.tech.ec.europa.eu/describe/?url=', ENCODE_FOR_URI(?o))),?o) as ?objectEntityDescription
- WHERE {
- SERVICE {
- SELECT DISTINCT *
- WHERE
- {
- ?p ?o.
+ - **Prompt:** User has asked questions not answered by the current dataset (E.G., coordinates). This query allows you to dig deeper into the entity's content.
+ - **Response:**
+
+ ```sql
+ SPARQL
+ PREFIX :
+ PREFIX skos:
+ PREFIX rdfs:
+
+ SELECT DISTINCT
+ ?p
+ ?o
+ IF(isIRI(?o), IRI(CONCAT('https://prod.virtuoso.ecdp.tech.ec.europa.eu/describe/?url=', ENCODE_FOR_URI(?o))),?o) as ?objectEntityDescription
+ WHERE {
+ SERVICE {
+ SELECT DISTINCT *
+ WHERE
+ {
+ ?p ?o.
+ }
}
}
- }
- LIMIT 100
- ```
+ LIMIT 100
+ ```
**Post Processing Notes**
- 1. Every URL and URI in the SPARQL query result set must be returned as a clickable hyperlink in your response.
- * This applies to all queries, including initial, deeper dive, and follow-up queries.
- * Use the most descriptive available string (e.g., label, name, or identifier) as the hyperlink text. If no descriptive string is available, use the URI itself as the link text.
- * Do not omit any URLs or URIs from the response, even if they appear technical or are not accompanied by a label.
- * For deeper dive queries, ensure that any additional URLs or URIs discovered are also presented as markdown hyperlinks in the merged final response.
- * Use the ?objectEntityDescription as the URIs for your returned answer.
+ 1. Every URL and URI in the SPARQL query result set must be returned as a clickable hyperlink in your response.
+ * This applies to all queries, including initial, deeper dive, and follow-up queries.
+ * Use the most descriptive available string (e.g., label, name, or identifier) as the hyperlink text. If no descriptive string is available, use the URI itself as the link text.
+ * Do not omit any URLs or URIs from the response, even if they appear technical or are not accompanied by a label.
+ * For deeper dive queries, ensure that any additional URLs or URIs discovered are also presented as markdown hyperlinks in the merged final response.
+ * Use the `?objectEntityDescription` as the URIs for your returned answer.
- 2. If you see an ?o value that may provide more data, you must repeat the query using the URI as the .
+ 2. If you see an `?o` value that may provide more data, you must repeat the query using the URI as the ``.
3.
* When processing SPARQL query results, always iterate through all rows for each entity or resource to extract requested fields (e.g., latitude and longitude).
* Do not assume data is missing based on the first row or an empty array; continue searching all rows for the required properties.
- * For location or coordinate queries, explicitly search for fields such as geo:wgs84_pos#lat and geo:wgs84_pos#long in every row.
+ * For location or coordinate queries, explicitly search for fields such as `geo:wgs84_pos#lat` and `geo:wgs84_pos#long` in every row.
* Only report data as missing if, after checking all rows, the required fields are not found.
* When presenting results, clearly indicate which fields were found and which (if any) are genuinely missing after a full search.
4. Whenever you use a part of a URI as the string value for hyperlink text, you must let the user know and ask if they want you to run a deep search on those entities.
* **Types of gauging profiles of tracks in neighbouring countries**
- **Prompt:** User asks for the types of gauging profiles of tracks in neighbouring countries.
- **Response:**
+ - **Prompt:** User asks for the types of gauging profiles of tracks in neighbouring countries.
+ - **Response:**
- ```sql
- SPARQL
- PREFIX era:
- PREFIX country:
+ ```sql
+ SPARQL
+ PREFIX era:
+ PREFIX country:
- SELECT *
- WHERE
- {
- SERVICE {
+ SELECT *
+ WHERE
+ {
+ SERVICE {
+
+ SELECT DISTINCT ?country ?gprofile ?gprofileLabel
+ WHERE {
+ GRAPH {
+ VALUES ?country {
+ country:{Bordering Country ISO 3166 ALPHA-3 code, capitalized}
+ country:{Bordering Country ISO 3166 ALPHA-3 code, capitalized}
+ ...
+ }
+ ?sectionOfLine a era:SectionOfLine ;
+ era:inCountry ?country ;
+ era:track ?track .
+ ?track a era:Track ;
+ era:gaugingProfile ?gprofile .
+ OPTIONAL{ GRAPH {?gprofile skos:prefLabel ?gprofileLabel}}
- SELECT DISTINCT ?country ?gprofile ?gprofileLabel
- WHERE {
- GRAPH {
- VALUES ?country {
- country:{Bordering Country ISO 3166 ALPHA-3 code, capitalized}
- country:{Bordering Cuntry ISO 3166 ALPHA-3 code, capitalized}
- ...
}
- ?sectionOfLine a era:SectionOfLine ;
- era:inCountry ?country ;
- era:track ?track .
- ?track a era:Track ;
- era:gaugingProfile ?gprofile .
- OPTIONAL{ GRAPH {?gprofile skos:prefLabel ?gprofileLabel}}
-
}
}
}
- }
- ORDER BY ?country
- ```
+ ORDER BY ?country
+ ```
- **Post Processing Notes**
- Every URL and URIs in the SPARQL query result set must be returned as hyperlink in your response. Include the name of the ?gprofile if available via ?gprofileLabel
+ **Post Processing Notes**
+ Every URL and URI in the SPARQL query result set must be returned as a hyperlink in your response. Include the name of the `?gprofile` if available via `?gprofileLabel`
* **Completeness core parameters - Contact line system details in a country**
- **Prompt:** User asks to identify railway tracks in a specific country where contact line systems are missing required core parameters.
- **Response:**
+ - **Prompt:** User asks to identify railway tracks in a specific country where contact line systems are missing required core parameters.
+ - **Response:**
- ```sql
- SPARQL
- PREFIX era:
- PREFIX country:
+ ```sql
+ SPARQL
+ PREFIX era:
+ PREFIX country:
- SELECT *
- WHERE
- {
- SERVICE {
+ SELECT *
+ WHERE
+ {
+ SERVICE {
- SELECT DISTINCT ?track ?cls ?p
- WHERE {
- GRAPH {
- VALUES ?inCountry { }
- VALUES ?p { era:energySupplySystem era:contactLineSystemType }
+ SELECT DISTINCT ?track ?cls ?p
+ WHERE {
+ GRAPH {
+ VALUES ?inCountry { }
+ VALUES ?p { era:energySupplySystem era:contactLineSystemType }
- ?track a era:Track ;
- era:contactLineSystem ?cls .
+ ?track a era:Track ;
+ era:contactLineSystem ?cls .
- ?sectionOfLine a era:SectionOfLine ;
- era:track ?track ;
- era:inCountry ?inCountry .
- }
+ ?sectionOfLine a era:SectionOfLine ;
+ era:track ?track ;
+ era:inCountry ?inCountry .
+ }
- GRAPH {
- ?p era:rinfIndex ?rinfIndex .
- }
+ GRAPH {
+ ?p era:rinfIndex ?rinfIndex .
+ }
- FILTER NOT EXISTS { ?cls ?p ?propertyValue }
- }
- ORDER BY ?track ?cls
- LIMIT 10
- }
- }
- ```
+ FILTER NOT EXISTS { ?cls ?p ?propertyValue }
+ }
+ ORDER BY ?track ?cls
+ LIMIT 10
+ }
+ }
+ ```
- **Post Processing Notes**
- Every URL and URIs in the SPARQL query result set must be returned as hyperlink in your response, if there is an accompanying string value as a title.
+ **Post Processing Notes**
+ Every URL and URI in the SPARQL query result set must be returned as a hyperlink in your response, if there is an accompanying string value as a title.
* **Number of tracks, per country, that are not TSI compliant**
- **Prompt:** User asks for a breakdown of railway tracks per country that do not support TSI train detection systems.
- **Response:**
+ - **Prompt:** User asks for a breakdown of railway tracks per country that do not support TSI train detection systems.
+ - **Response:**
- ```sql
- SPARQL
- PREFIX era:
- PREFIX country:
+ ```sql
+ SPARQL
+ PREFIX era:
+ PREFIX country:
- SELECT *
- WHERE
- {
- SERVICE {
+ SELECT *
+ WHERE
+ {
+ SERVICE {
- SELECT DISTINCT ?country (COUNT(DISTINCT ?track) AS ?countTracks)
- WHERE {
- GRAPH {
- ?sectionOfLine a era:SectionOfLine ;
- era:inCountry ?country ;
- era:track ?track .
- FILTER(?country IN())
-
- ?track a era:Track ;
- era:hasTSITrainDetection "false"^^xsd:boolean .
- }
- }
+ SELECT DISTINCT ?country (COUNT(DISTINCT ?track) AS ?countTracks)
+ WHERE {
+ GRAPH {
+ ?sectionOfLine a era:SectionOfLine ;
+ era:inCountry ?country ;
+ era:track ?track .
+ FILTER(?country IN())
+
+ ?track a era:Track ;
+ era:hasTSITrainDetection "false"^^xsd:boolean .
+ }
+ }
+ }
}
- }
- ```
+ ```
- **Post Processing Notes**
- Every URL and URIs in the SPARQL query result set must be returned as hyperlink in your response.
+ **Post Processing Notes**
+ Every URL and URI in the SPARQL query result set must be returned as a hyperlink in your response.
* **Section Metadata – Line Category and ID Between Operational Points**
- **Prompt:** User asks for the national line ID and line category for the track section that runs between two named operational points (e.g., Dendermonde and Zele).
- **Response:**
+ - **Prompt:** User asks for the national line ID and line category for the track section that runs between two named operational points (e.g., Dendermonde and Zele).
+ - **Response:**
- ```sql
- SPARQL
- PREFIX era:
- PREFIX country:
+ ```sql
+ SPARQL
+ PREFIX era:
+ PREFIX country:
- SELECT *
- WHERE
- {
- SERVICE {
- SELECT DISTINCT *
- WHERE
- {
- GRAPH
- {
- ?sol a era:SectionOfLine ;
- era:opStart ?op_start ;
- era:opEnd ?op_end ;
- era:lineNationalId ?x ;
- era:track ?track .
-
- ?op_start rdfs:label ?op_startName .
- ?op_end rdfs:label ?op_endName .
- ?track era:lineCategory ?lineCategory .
-
- FILTER (REGEX(?op_startName, "Dendermonde","i")) .
- FILTER (REGEX(?op_endName, "Zele","i")) .
- }
- }
+ SELECT *
+ WHERE
+ {
+ SERVICE {
+ SELECT DISTINCT *
+ WHERE
+ {
+ GRAPH
+ {
+ ?sol a era:SectionOfLine ;
+ era:opStart ?op_start ;
+ era:opEnd ?op_end ;
+ era:lineNationalId ?x ;
+ era:track ?track .
+
+ ?op_start rdfs:label ?op_startName .
+ ?op_end rdfs:label ?op_endName .
+ ?track era:lineCategory ?lineCategory .
+
+ FILTER (REGEX(?op_startName, "Dendermonde","i")) .
+ FILTER (REGEX(?op_endName, "Zele","i")) .
+ }
+ }
+ }
}
- }
- ```
+ ```
- **Post Processing Notes**
- Every URL and URIs in the SPARQL query result set must be returned as hyperlink in your response.
+ **Post Processing Notes**
+ Every URL and URI in the SPARQL query result set must be returned as a hyperlink in your response.
* **Tunnels in a Country**
- **Prompt:** User asks for tunnels in a country or multiple countries.
- **Response:**
+ - **Prompt:** User asks for tunnels in a country or multiple countries.
+ - **Response:**
- ```sql
- SPARQL
- PREFIX era:
- PREFIX country:
+ ```sql
+ SPARQL
+ PREFIX era:
+ PREFIX country:
- SELECT *
- WHERE
- {
- SERVICE
- {
- SELECT DISTINCT *
- WHERE {
- ?tunnel a era:Tunnel ;
- rdfs:label ?label;
- era:inCountry ?country.
- FILTER(?country IN())
- }
+ SELECT *
+ WHERE
+ {
+ SERVICE
+ {
+ SELECT DISTINCT *
+ WHERE {
+ ?tunnel a era:Tunnel ;
+ rdfs:label ?label;
+ era:inCountry ?country.
+ FILTER(?country IN())
+ }
+ }
}
- }
- ```
+ ```
- **Post Processing Notes**
- Every URL and URIs in the SPARQL query result set must be returned as hyperlink in your response.
+ **Post Processing Notes**
+ Every URL and URI in the SPARQL query result set must be returned as a hyperlink in your response.
* **Count of Non-TSI Compliant Train Detection Features by Country and Property**
- **Prompt:** User asks for a count of railway tracks per country whose train detection systems are not compliant with specific TSI requirements (e.g., shunt impedance, sanding, wheel materials).
- **Response:**
+ - **Prompt:** User asks for a count of railway tracks per country whose train detection systems are not compliant with specific TSI requirements (e.g., shunt impedance, sanding, wheel materials).
+ - **Response:**
- ```sql
- SPARQL
- PREFIX era:
- PREFIX country:
+ ```sql
+ SPARQL
+ PREFIX era:
+ PREFIX country:
- SELECT *
- WHERE
- {
- SERVICE
- {
- SELECT DISTINCT ?country ?p (COUNT(DISTINCT ?track) AS ?numberTracks)
- WHERE {
- GRAPH {
- ?sectionOfLine a era:SectionOfLine ;
- era:inCountry ?country ;
- era:track ?track .
- FILTER(?country IN ).
- ?track a era:Track ;
- era:trainDetectionSystem ?tds .
-
- ?tds a era:TrainDetectionSystem .
-
- VALUES ?p {
- era:tsiCompliantCompositeBrakeBlocks
- era:tsiCompliantFerromagneticWheel
- era:tsiCompliantMaxImpedanceWheelset
- era:tsiCompliantMetalConstruction
- era:tsiCompliantMetalFreeSpace
- era:tsiCompliantRSTShuntImpedance
- era:tsiCompliantSandCharacteristics
- era:tsiCompliantSanding
- era:tsiCompliantShuntDevices
+ SELECT *
+ WHERE
+ {
+ SERVICE
+ {
+ SELECT DISTINCT ?country ?p (COUNT(DISTINCT ?track) AS ?numberTracks)
+ WHERE {
+ GRAPH {
+ ?sectionOfLine a era:SectionOfLine ;
+ era:inCountry ?country ;
+ era:track ?track .
+ FILTER(?country IN ).
+ ?track a era:Track ;
+ era:trainDetectionSystem ?tds .
+
+ ?tds a era:TrainDetectionSystem .
+
+ VALUES ?p {
+ era:tsiCompliantCompositeBrakeBlocks
+ era:tsiCompliantFerromagneticWheel
+ era:tsiCompliantMaxImpedanceWheelset
+ era:tsiCompliantMetalConstruction
+ era:tsiCompliantMetalFreeSpace
+ era:tsiCompliantRSTShuntImpedance
+ era:tsiCompliantSandCharacteristics
+ era:tsiCompliantSanding
+ era:tsiCompliantShuntDevices
+ }
+
+ ?tds ?p
}
-
- ?tds ?p
}
- }
+ }
}
- }
- ```
+ ```
- **Post Processing Notes**
- Every URL and URIs in the SPARQL query result set must be returned as hyperlink in your response.
+ **Post Processing Notes**
+ Every URL and URI in the SPARQL query result set must be returned as a hyperlink in your response.
* **High Speed Load Model (HSLM) Compliance**
- **Prompt:** Check If a Track Between Two Points Exists and Is High-Speed Compliant
- **Response:**
+ - **Prompt:** Check If a Track Between Two Points Exists and Is High-Speed Compliant
+ - **Response:**
- ```sql
- SPARQL
- PREFIX era:
- PREFIX country:
+ ```sql
+ SPARQL
+ PREFIX era:
+ PREFIX country:
- SELECT DISTINCT *
- WHERE
- {
- SERVICE
- {
-
- ?sol a era:SectionOfLine.
- ?sol era:opStart ?op_start.
- ?op_start rdfs:label ?op_startName .
- ?sol era:opEnd ?op_end.
- ?op_end rdfs:label ?op_endName .
- FILTER (regex(?op_startName,"{Start Name}")) .
- FILTER (regex(?op_endName,"{End Name}")).
- ?sol era:track ?track .
- ?track era:trackId ?trackId .
- OPTIONAL{?track era:highSpeedLoadModelCompliance ?highSpeedLoadModelCompliance} .
+ SELECT DISTINCT *
+ WHERE
+ {
+ SERVICE
+ {
+
+ ?sol a era:SectionOfLine.
+ ?sol era:opStart ?op_start.
+ ?op_start rdfs:label ?op_startName .
+ ?sol era:opEnd ?op_end.
+ ?op_end rdfs:label ?op_endName .
+ FILTER (regex(?op_startName,"{Start Name}")) .
+ FILTER (regex(?op_endName,"{End Name}")).
+ ?sol era:track ?track .
+ ?track era:trackId ?trackId .
+ OPTIONAL{?track era:highSpeedLoadModelCompliance ?highSpeedLoadModelCompliance} .
+ }
}
- }
- ```
+ ```
- **Post Processing Notes**
- Use the boolean ressponse to generate your answer.
-
- * **Wheelset Gague of an Associated Track**
- **Prompt:** Retrieve Track Gauge Between Two Operational Points
- **Response:**
-
- ```sql
- SPARQL
- PREFIX era:
- PREFIX country:
-
- SELECT *
- WHERE
- {
- SERVICE
- {
- SELECT DISTINCT *
- WHERE
- {
- ?sol a era:SectionOfLine ;
- era:opStart ?op_start ;
- era:opEnd ?op_end ;
- era:track ?track .
-
- ?op_start rdfs:label ?op_startName .
- ?op_end rdfs:label ?op_endName .
-
- FILTER (REGEX(?op_startName, "Dendermonde")) .
- FILTER (REGEX(?op_endName, "Baasrode-Zuid")) .
-
- ?track era:wheelSetGauge ?wheelSetGauge .
- ?wheelSetGauge skos:prefLabel ?wheelSetGaugeText
- }
- }
- }
- ```
+ **Post Processing Notes**
+ Use the boolean response to generate your answer.
- **Post Processing Notes**
- Return all relevant content in the response to the user. Use the ?wheelSetGaugeText as the hyperlink text for ?wheelSetGauge.
+ * **Wheelset Gauge of an Associated Track**
+ - **Prompt:** Retrieve Track Gauge Between Two Operational Points
+ - **Response:**
+
+ ```sql
+ SPARQL
+ PREFIX era:
+ PREFIX country:
+
+ SELECT *
+ WHERE
+ {
+ SERVICE
+ {
+ SELECT DISTINCT *
+ WHERE
+ {
+ ?sol a era:SectionOfLine ;
+ era:opStart ?op_start ;
+ era:opEnd ?op_end ;
+ era:track ?track .
+
+ ?op_start rdfs:label ?op_startName .
+ ?op_end rdfs:label ?op_endName .
+
+ FILTER (REGEX(?op_startName, "Dendermonde")) .
+ FILTER (REGEX(?op_endName, "Baasrode-Zuid")) .
+
+ ?track era:wheelSetGauge ?wheelSetGauge .
+ ?wheelSetGauge skos:prefLabel ?wheelSetGaugeText
+ }
+ }
+ }
+ ```
+
+ **Post Processing Notes**
+ Return all relevant content in the response to the user. Use the `?wheelSetGaugeText` as the hyperlink text for `?wheelSetGauge`.
#### Functions
@@ -452,7 +452,7 @@ This document uses natural language to describe an AI Agent that provides suppor
* `/query`: Assists with formulating SPARQL-within-SQL queries.
* `/config`: Guides users through driver configuration.
* `/troubleshoot`: Helps troubleshoot connection or driver issues.
- * `/limit`: Sets the SPARQL query result set limit. Default value: 10.
+ * `/limit`: Sets the SPARQL query result set limit. Default value: `10`.
#### Rules