code: def colors(self, value):
          
          if value is not None:
              assert type(value) is tuple, "'{0}' attribute: '{1}' type is not 'tuple'!".format("colors", value)
              assert len(value) == 2, "'{0}' attribute: '{1}' length should be '2'!".format("colors", value)
              for index in range(len(value)):
                  assert type(
                      value[index]) is QColor, "'{0}' attribute element '{1}': '{2}' type is not 'QColor'!".format(
                      "colors", index, value)
          self.__colors = value
docs: Setter for **self.__colors** attribute.
  
          :param value: Attribute value.
          :type value: tuple