def retrieve(self, id) :
        """
        Retrieve a single source

        Returns a single source available to the user by the provided id
        If a source with the supplied unique identifier does not exist it returns an error

        :calls: ``get /lead_sources/{id}``
        :param int id: Unique identifier of a LeadSource.
        :return: Dictionary that support attriubte-style access and represent LeadSource resource.
        :rtype: dict
        """

        _, _, lead_source = self.http_client.get("/lead_sources/{id}".format(id=id))
        return lead_source