code: def pythonize(self, val):
          
          if isinstance(val, list):
              return [s.strip() if hasattr(s, "strip") else s
                      for s in list_split(val, self.split_on_comma)
                      if hasattr(s, "strip") and s.strip() != '' or self.keep_empty]
  
          return [s.strip() if hasattr(s, "strip") else s
                  for s in to_split(val, self.split_on_comma)
                  if hasattr(s, "strip") and s.strip() != '' or self.keep_empty]
docs: Convert value into a list::
  
          * split value (or each element if value is a list) on coma char
          * strip split values
  
          :param val: value to convert
          :type val: str
          :return: list corresponding to value
          :rtype: list