Fix travis style issues

Author: codingS3b

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

@@ -1,7 +1,18 @@
-import matplotlib.pyplot as plt
+"""
+This file is part of the PIConGPU.
+
+Copyright 2017-2018 PIConGPU contributors
+Authors: Sebastian Starke
+License: GPLv3+
+"""
 
+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:

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

@@ -39,12 +39,13 @@ def _create_data_reader(self, run_directory):
     def _create_plt_obj(self, ax):
         dat, meta = self.data
         self.plt_obj = ax.imshow(
-        np.abs(dat).T * meta.dV,
-        extent=meta.extent * [self.mu, self.mu, self.e_mc_r, self.e_mc_r],
-        interpolation='nearest',
-        aspect='auto',
-        origin='lower',
-        norm=LogNorm())
+            np.abs(dat).T * meta.dV,
+            extent=meta.extent * [self.mu, self.mu, self.e_mc_r, self.e_mc_r],
+            interpolation='nearest',
+            aspect='auto',
+            origin='lower',
+            norm=LogNorm()
+        )
 
     def _update_plt_obj(self):
         dat, meta = self.data
@@ -76,7 +77,6 @@ def visualize(self, ax=None, **kwargs):
         super(Visualizer, self).visualize(ax, **kwargs)
 
         _, meta = self.data
-        species = kwargs.get('species')
         # prevent multiple rendering of colorbar
         if not self.plt_obj.colorbar:
             cbar = plt.colorbar(self.plt_obj, ax=ax)

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

@@ -6,8 +6,6 @@
 License: GPLv3+
 """
 
-import os
-import numpy as np
 from picongpu.plugins.png import PNG
 from picongpu.plugins.plot_mpl.base_visualizer import Visualizer as\
     BaseVisualizer, plt

lib/python/picongpu/plugins/png.py

@@ -7,7 +7,6 @@
 """
 
 import os
-import numpy as np
 import matplotlib.image as mpimg
 import collections