Collated PEP8 fixes (#25293)

- Make PEP8 compliant

lib/ansible/plugins/test/mathstuff.py

@@ -20,18 +20,22 @@ __metaclass__ = type
 
 import math
 
+
 def issubset(a, b):
     return set(a) <= set(b)
 
+
 def issuperset(a, b):
     return set(a) >= set(b)
 
+
 def isnotanumber(x):
     try:
         return math.isnan(x)
     except TypeError:
         return False
 
+
 class TestModule:
     ''' Ansible math jinja2 tests '''