No need to check that strings are hashable.

anntzer · anntzer · commit 7b05193901ff · 2017-04-16T00:23:48.000-07:00
diff --git a/lib/matplotlib/collections.py b/lib/matplotlib/collections.py
@@ -511,7 +511,7 @@ def set_linestyle(self, ls):
             The line style.
         """
         try:
-            if isinstance(ls, six.string_types) and cbook.is_hashable(ls):
+            if isinstance(ls, six.string_types):
                 ls = cbook.ls_mapper.get(ls, ls)
                 dashes = [mlines._get_dash_pattern(ls)]
             else:
diff --git a/lib/matplotlib/lines.py b/lib/matplotlib/lines.py
@@ -16,7 +16,7 @@
 from . import artist, colors as mcolors, docstring, rcParams
 from .artist import Artist, allow_rasterization
 from .cbook import (
-    iterable, is_numlike, ls_mapper, ls_mapper_r, is_hashable, STEP_LOOKUP_MAP)
+    iterable, is_numlike, ls_mapper, ls_mapper_r, STEP_LOOKUP_MAP)
 from .markers import MarkerStyle
 from .path import Path
 from .transforms import Bbox, TransformedPath, IdentityTransform
@@ -33,10 +33,9 @@
 
 def _get_dash_pattern(style):
     """Convert linestyle -> dash pattern
-
     """
     # go from short hand -> full strings
-    if isinstance(style, six.string_types) and is_hashable(style):
+    if isinstance(style, six.string_types):
         style = ls_mapper.get(style, style)
     # un-dashed styles
     if style in ['solid', 'None']:
