diff --git a/lib/matplotlib/units.py b/lib/matplotlib/units.py
index b85d84a4aaf6..0bbe697b54f8 100644
--- a/lib/matplotlib/units.py
+++ b/lib/matplotlib/units.py
@@ -43,11 +43,12 @@ def default_units(x, axis):
 
 """
 from __future__ import print_function
-import numpy as np
-from matplotlib.cbook import iterable, is_numlike, is_string_like
+from matplotlib.cbook import iterable, is_numlike
+
 
 class AxisInfo:
-    'information to support default axis labeling and tick labeling, and default limits'
+    """information to support default axis labeling and tick labeling, and
+       default limits"""
     def __init__(self, majloc=None, minloc=None,
                  majfmt=None, minfmt=None, label=None,
                  default_limits=None):
@@ -107,6 +108,7 @@ def is_numlike(x):
         else:
             return is_numlike(x)
 
+
 class Registry(dict):
     """
     register types with conversion interface
@@ -118,7 +120,8 @@ def __init__(self):
     def get_converter(self, x):
         'get the converter interface instance for x, or None'
 
-        if not len(self): return None # nothing registered
+        if not len(self):
+            return None  # nothing registered
         #DISABLED idx = id(x)
         #DISABLED cached = self._cached.get(idx)
         #DISABLED if cached is not None: return cached
@@ -131,11 +134,11 @@ def get_converter(self, x):
 
         if converter is None and iterable(x):
             for thisx in x:
-                # Make sure that recursing might actually lead to a solution, if
-                # we are just going to re-examine another item of the same kind,
-                # then do not look at it.
+                # Make sure that recursing might actually lead to a solution,
+                # if we are just going to re-examine another item of the same
+                # kind, then do not look at it.
                 if classx and classx != getattr(thisx, '__class__', None):
-                    converter = self.get_converter( thisx )
+                    converter = self.get_converter(thisx)
                     return converter
 
         #DISABLED self._cached[idx] = converter