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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def dimensions_unit(self, dimensions_unit):
 """Sets the dimensions_unit of this MeasurementSettings. :param dimensions_unit: The dimensions_unit of this MeasurementSettings. :type: str """

        allowed_values = ["inch", "cm", "foot", "meter"]  # noqa: E501
        if dimensions_unit is not None and dimensions_unit not in allowed_values:
            raise ValueError(
                "Invalid value for `dimensions_unit` ({0}), must be one of {1}"  # noqa: E501
                .format(dimensions_unit, allowed_values)
            )

        self._dimensions_unit = dimensions_unit