Reversed former changes, no need for math module.

pylot/core/util/widgets.py

@@ -9,7 +9,6 @@ import warnings
 import copy
 import datetime
 import numpy as np
-import math
 
 from matplotlib.figure import Figure
 from pylot.core.util.utils import find_horizontals
@@ -243,7 +242,6 @@ class ComparisonDialog(QDialog):
                                          std=std, exp=exp)
         bbox_props = dict(boxstyle='round', facecolor='lightgrey', alpha=.7)
 
-        if math.isnan(std) == False:
         plot_pdf(_axes, x, y, annotation, bbox_props, 'time difference [s]',
                   'propability density [-]', phase)