def add_acquisition_source(
        self,
        method,
        submission_number=None,
        internal_uid=None,
        email=None,
        orcid=None,
        source=None,
        datetime=None,
    ):
        """Add acquisition source.

        :type submission_number: integer

        :type email: integer

        :type source: string

        :param method: method of acquisition for the suggested document
        :type method: string

        :param orcid: orcid of the user that is creating the record
        :type orcid: string

        :param internal_uid: id of the user that is creating the record
        :type internal_uid: string

        :param datetime: UTC datetime in ISO 8601 format
        :type datetime: string
        """
        acquisition_source = self._sourced_dict(source)

        acquisition_source['submission_number'] = str(submission_number)
        for key in ('datetime', 'email', 'method', 'orcid', 'internal_uid'):
            if locals()[key] is not None:
                acquisition_source[key] = locals()[key]

        self.obj['acquisition_source'] = acquisition_source