Sets the expected_duration of this ModelBreak.
        Format: RFC-3339 P[n]Y[n]M[n]DT[n]H[n]M[n]S. The expected length of the break.

        :param expected_duration: The expected_duration of this ModelBreak.
        :type: str

def expected_duration(self, expected_duration):
        """
        Sets the expected_duration of this ModelBreak.
        Format: RFC-3339 P[n]Y[n]M[n]DT[n]H[n]M[n]S. The expected length of the break.

        :param expected_duration: The expected_duration of this ModelBreak.
        :type: str
        """

        if expected_duration is None:
            raise ValueError("Invalid value for `expected_duration`, must not be `None`")
        if len(expected_duration) < 1:
            raise ValueError("Invalid value for `expected_duration`, length must be greater than or equal to `1`")

        self._expected_duration = expected_duration