fix further style issues

Author: codingS3b

lib/python/picongpu/plugins/plot_mpl/base_visualizer.py

@@ -8,11 +8,13 @@
 
 import matplotlib.pyplot as plt
 
+
 class Visualizer(object):
     """
     Abstract base class for matplotlib visualizers that implements
     the visualization logic.
     """
+
     def __init__(self, run_directory):
 
         if run_directory is None:
@@ -56,7 +58,7 @@ def visualize(self, ax=None, **kwargs):
         """
         if ax is None:
             raise ValueError("A matplotlib axes object needs to be passed!")
-        
+
         self.data = self.data_reader.get(**kwargs)
         if self.plt_obj is None:
             self._create_plt_obj(ax)

lib/python/picongpu/plugins/plot_mpl/energy_histogram_visualizer.py

@@ -52,7 +52,7 @@ def visualize(self, ax=None, **kwargs):
                 (defined in ``particleFilters.param``)
 
         """
-        ax=self._ax_or_gca(ax)
+        ax = self._ax_or_gca(ax)
         # this already throws error if no species or iteration in kwargs
         super(Visualizer, self).visualize(ax, **kwargs)
         iteration = kwargs.get('iteration')