matplotlib
diff --git a/‎lib/matplotlib/axes/_axes.py
Lines changed: 7 additions & 4 deletions b/‎lib/matplotlib/axes/_axes.py
Lines changed: 7 additions & 4 deletions
diff --git a/‎lib/matplotlib/pyplot.py
Lines changed: 1 addition & 1 deletion b/‎lib/matplotlib/pyplot.py
Lines changed: 1 addition & 1 deletion
@@ -6870,15 +6870,15 @@ def matshow(self, Z, **kwargs):
 
     def violinplot(self, dataset, positions=None, vert=True, widths=0.5,
                    showmeans=False, showextrema=True, showmedians=False,
-                   points=100, bw_method=None, color='y', line_kw={},
+                   points=100, bw_method=None, color='y', line_kw=None,
                    **fill_kw):
         """Make a violin plot.
 
         Call signature::
 
           violinplot(dataset, positions=None, vert=True, widths=0.5,
                      showmeans=False, showextrema=True, showmedians=False,
-                     points=100, bw_method=None, color='y', line_kw={},
+                     points=100, bw_method=None, color='y', line_kw=None,
                      **fill_kw):
 
         Make a violin plot for each column of *dataset* or each vector in
@@ -6986,14 +6986,14 @@ def _kde_method(X, coords):
 
     def violin(self, vpstats, positions=None, vert=True, widths=0.5,
                showmeans=False, showextrema=True, showmedians=False,
-               color='y', line_kw={}, **fill_kw):
+               color='y', line_kw=None, **fill_kw):
         """Drawing function for violin plots.
 
         Call signature::
 
           violin(vpstats, positions=None, vert=True, widths=0.5,
                  showmeans=False, showextrema=True, showmedians=False,
-                 color='y', line_kw={}, **fill_kw):
+                 color='y', line_kw=None, **fill_kw):
 
         Draw a violin plot for each column of `vpstats`. Each filled area
         extends to represent the entire data range, with optional lines at the
@@ -7124,6 +7124,9 @@ def violin(self, vpstats, positions=None, vert=True, widths=0.5,
         elif len(color) != N:
             raise ValueError(datashape_message.format("color"))
 
+        if line_kw is None:
+            line_kw = {}
+
         # original default values for line color and alpha
         line_color = line_kw.pop('colors', 'r')
         alpha = fill_kw.pop('alpha', 0.3)
 
@@ -3420,7 +3420,7 @@ def triplot(*args, **kwargs):
 @_autogen_docstring(Axes.violinplot)
 def violinplot(dataset, positions=None, vert=True, widths=0.5, showmeans=False,
                showextrema=True, showmedians=False, points=100, bw_method=None,
-               color='y', line_kw={}, hold=None, **fill_kw):
+               color='y', line_kw=None, hold=None, **fill_kw):
     ax = gca()
     # allow callers to override the hold state by passing hold=True|False
     washold = ax.ishold()