def set_context_params(self, params):

        """ Set header context parameters. Refer to the top of <Zimbra
        Server-Root>/docs/soap.txt about specifics.

        The <format>-Parameter cannot be changed, because it is set by the
        implementing class.

        Should be called by implementing method to check for valid context
        params.

        :param params: A Dict containing context parameters.
        """

        for key, value in params.items():

            if key not in self.valid_context_params:

                raise RequestHeaderContextException(
                    "%s is not a valid context parameter." % key
                )
Set header context parameters. Refer to the top of <Zimbra
        Server-Root>/docs/soap.txt about specifics.

        The <format>-Parameter cannot be changed, because it is set by the
        implementing class.

        Should be called by implementing method to check for valid context
        params.

        :param params: A Dict containing context parameters.