fix: nit fixes for API Registry - updating imports / type hints and formatting

Co-authored-by: Kathy Wu <wukathy@google.com>
PiperOrigin-RevId: 845980315

Author: wukath

src/google/adk/tools/api_registry.py

@@ -17,11 +17,8 @@
 import sys
 from typing import Any
 from typing import Callable
-from typing import Dict
-from typing import List
-from typing import Optional
-from typing import Union
 
+from google.adk.agents.readonly_context import ReadonlyContext
 import google.auth
 import google.auth.transport.requests
 import httpx
@@ -40,9 +37,9 @@ def __init__(
       self,
       api_registry_project_id: str,
       location: str = "global",
-      header_provider: Optional[
-          Callable[[ReadonlyContext], Dict[str, str]]
-      ] = None,
+      header_provider: (
+          Callable[[ReadonlyContext], dict[str, str]] | None
+      ) = None,
   ):
     """Initialize the API Registry.
 
@@ -55,7 +52,7 @@ def __init__(
     self.api_registry_project_id = api_registry_project_id
     self.location = location
     self._credentials, _ = google.auth.default()
-    self._mcp_servers: Dict[str, Dict[str, Any]] = {}
+    self._mcp_servers: dict[str, dict[str, Any]] = {}
     self._header_provider = header_provider
 
     url = f"{API_REGISTRY_URL}/v1beta/projects/{self.api_registry_project_id}/locations/{self.location}/mcpServers"
@@ -79,14 +76,13 @@ def __init__(
   def get_toolset(
       self,
       mcp_server_name: str,
-      tool_filter: Optional[Union[ToolPredicate, List[str]]] = None,
-      tool_name_prefix: Optional[str] = None,
+      tool_filter: ToolPredicate | list[str] | None = None,
+      tool_name_prefix: str | None = None,
   ) -> McpToolset:
     """Return the MCP Toolset based on the params.
 
     Args:
-      mcp_server_name: Filter to select the MCP server name to get tools
-        from.
+      mcp_server_name: Filter to select the MCP server name to get tools from.
       tool_filter: Optional filter to select specific tools. Can be a list of
         tool names or a ToolPredicate function.
       tool_name_prefix: Optional prefix to prepend to the names of the tools
@@ -116,14 +112,15 @@ def get_toolset(
         header_provider=self._header_provider,
     )
 
-  def _get_auth_headers(self) -> Dict[str, str]:
+  def _get_auth_headers(self) -> dict[str, str]:
     """Refreshes credentials and returns authorization headers."""
     request = google.auth.transport.requests.Request()
     self._credentials.refresh(request)
     headers = {
         "Authorization": f"Bearer {self._credentials.token}",
     }
     # Add quota project header if available in ADC
-    if self._credentials.quota_project_id:
-      headers["x-goog-user-project"] = self._credentials.quota_project_id
+    quota_project_id = getattr(self._credentials, "quota_project_id", None)
+    if quota_project_id:
+      headers["x-goog-user-project"] = quota_project_id
     return headers