docs: def comment_marker(self, value):
          """
          Setter for **self.__comment_marker** attribute.
  
          :param value: Attribute value.
          :type value: unicode
          """
  
          if value is not None:
              assert type(value) is unicode, "'{0}' attribute: '{1}' type is not 'unicode'!".format(
                  "comment_marker", value)
              assert not re.search(r"\w", value), "'{0}' attribute: '{1}' is an alphanumeric character!".format(
                  "comment_marker", value)
          self.__comment_marker = value