Sample arcpy helper function - get not null fields

get_not_null_fields.py

import arcpy

def get_fields(input_fc,only_field_type="String",not_null=True):
  '''returns list of field names of specified data type and contain at
  least one not NULL value'''

  if not not_null:
    all_fields = [field.name for field in arcpy.ListFields(in_fc,field_type=only_field_type)]
    return all_fields

  else:
    all_fields = [field.name for field in arcpy.ListFields(in_fc,field_type=only_field_type)
                  if field.isNullable != "False"]
    #getting a dict {field name : [list of all values]}
    fields_dict = {field: list(set([feature[all_fields.index(field)]
                                  for feature in arcpy.da.SearchCursor(in_fc,all_fields)]))
                 for field in all_fields}
    null_fields = [k for k,v in fields_dict.iteritems() if v == [None]]
    not_null_fields = list(set(all_fields).symmetric_difference(set(null_fields)))

    return not_null_fields