Change cbook.iterable to np.iterable

Matplotlib 3.1.0 has deprecated cbook.iterable.

plotnine/utils.py

@@ -11,7 +11,6 @@
 import numpy as np
 import pandas as pd
 import pandas.api.types as pdtypes
-import matplotlib.cbook as cbook
 import matplotlib.colors as mcolors
 from matplotlib.colors import colorConverter
 from matplotlib.offsetbox import DrawingArea
@@ -33,7 +32,7 @@ def is_scalar_or_string(val):
     """
     Return whether the given object is a scalar or string like.
     """
-    return is_string(val) or not cbook.iterable(val)
+    return is_string(val) or not np.iterable(val)
 
 
 def is_string(obj):
@@ -51,7 +50,7 @@ def make_iterable(val):
 
     Strings are not recognized as iterables
     """
-    if cbook.iterable(val) and not is_string(val):
+    if np.iterable(val) and not is_string(val):
         return val
     return [val]
 
@@ -66,7 +65,7 @@ def make_iterable_ntimes(val, n):
     Raises an exception if *val* is an iterable but has length
     not equal to n
     """
-    if cbook.iterable(val) and not is_string(val):
+    if np.iterable(val) and not is_string(val):
         if len(val) != n:
             raise PlotnineError(
                 '`val` is an iterable of length not equal to n.')
@@ -554,7 +553,7 @@ def to_rgba(colors, alpha):
     list-likes and the alpha dimension will be respected.
     """
     def is_iterable(var):
-        return cbook.iterable(var) and not is_string(var)
+        return np.iterable(var) and not is_string(var)
 
     def has_alpha(c):
         if isinstance(c, tuple):