matplotlib · i-deal · Jan 18, 2023 · Jan 19, 2023 · Jan 19, 2023 · Jan 19, 2023
diff --git a/lib/matplotlib/colors.py b/lib/matplotlib/colors.py
@@ -243,6 +243,18 @@ def _check_color_like(**kwargs):
             raise ValueError(f"{v!r} is not a valid value for {k}")
 
 
+def _check_color_like_list(**kwargs):
+    """
+    For each *key, lst* pair in *kwargs*, check that every
+    element *v* in *lst* is color-like.
+    """
+    for k, lst in kwargs.items():
+        invalid_col = [c for c in lst if not is_color_like(c)]
+        if invalid_col:
+            err_msg = f"{invalid_col!r} are not valid values for {k}"
+            raise ValueError(err_msg)
+
+
 def same_color(c1, c2):
     """
     Return whether the colors *c1* and *c2* are the same.

diff --git a/lib/matplotlib/tests/test_colors.py b/lib/matplotlib/tests/test_colors.py
@@ -1,6 +1,7 @@
 import copy
 import itertools
 import unittest.mock
+from re import escape
 
 from io import BytesIO
 import numpy as np
@@ -1592,3 +1593,20 @@ def test_cm_set_cmap_error():
     bad_cmap = 'AardvarksAreAwkward'
     with pytest.raises(ValueError, match=bad_cmap):
         sm.set_cmap(bad_cmap)
+
+
+def test_check_color_like():
+    err_msg = "['abcd'] is not a valid value for c"
+    assert mcolors._check_color_like(colors1='yellow', colors2='red') is None
+    with pytest.raises(ValueError, match=err_msg):
+        mcolors._check_color_like(c='abcd')
+
+
+def test_check_color_like_list():
+    err_msg = escape("['abcd'] are not valid values for c")
+    assert mcolors._check_color_like_list(colors=['yellow', 'orange']) is None
+    assert mcolors._check_color_like_list(c1=['red'], c2=['blue']) is None
+    with pytest.raises(ValueError, match=err_msg):
+        mcolors._check_color_like_list(c=['abcd', 'red'])
+    with pytest.raises(ValueError, match=err_msg):
+        mcolors._check_color_like_list(c1=['red', 'blue'], c=['abcd'])