docs: def unit(self, unit):
          """Sets the unit of this Dimensions.
  
  
          :param unit: The unit of this Dimensions.
          :type: str
          """
          allowed_values = ["cm", "inch", "foot"]  # noqa: E501
          if unit is not None and unit not in allowed_values:
              raise ValueError(
                  "Invalid value for `unit` ({0}), must be one of {1}"  # noqa: E501
                  .format(unit, allowed_values)
              )
  
          self._unit = unit