diff --git a/pyproject.toml b/pyproject.toml
index 2ba8dad..600114b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -47,7 +47,7 @@ dev = [
 line-length = 99
 
 [tool.ruff.lint]
-extend-select = ["W", "I", "C90"]
+extend-select = ["W", "ISC", "I", "C90"]
 ignore = ["E721", "C901"]
 
 [tool.ruff.lint.mccabe]
diff --git a/tabulate/__init__.py b/tabulate/__init__.py
index c3f60d3..b0810a9 100644
--- a/tabulate/__init__.py
+++ b/tabulate/__init__.py
@@ -300,7 +300,7 @@ def make_header_line(is_header, colwidths, colaligns):
     else:
         raise ValueError(
             "_asciidoc_row() requires two (colwidths, colaligns) "
-            + "or three (cell_values, colwidths, colaligns) arguments) "
+            "or three (cell_values, colwidths, colaligns) arguments) "
         )
 
 
@@ -1409,7 +1409,7 @@ def _prepend_row_index(rows, index):
     if isinstance(index, Sized) and len(index) != len(rows):
         raise ValueError(
             "index must be as long as the number of data rows: "
-            + f"len(index)={len(index)} len(rows)={len(rows)}"
+            f"len(index)={len(index)} len(rows)={len(rows)}"
         )
     sans_rows, separating_lines = _remove_separating_lines(rows)
     new_rows = []