CreateUser.
        [Preview API] Materialize an existing AAD or MSA user into the VSTS account.
        :param :class:`<GraphUserCreationContext> <azure.devops.v5_1.graph.models.GraphUserCreationContext>` creation_context: The subset of the full graph user used to uniquely find the graph subject in an external provider.
        :param [str] group_descriptors: A comma separated list of descriptors of groups you want the graph user to join
        :rtype: :class:`<GraphUser> <azure.devops.v5_1.graph.models.GraphUser>`

def create_user(self, creation_context, group_descriptors=None):
        """CreateUser.
        [Preview API] Materialize an existing AAD or MSA user into the VSTS account.
        :param :class:`<GraphUserCreationContext> <azure.devops.v5_1.graph.models.GraphUserCreationContext>` creation_context: The subset of the full graph user used to uniquely find the graph subject in an external provider.
        :param [str] group_descriptors: A comma separated list of descriptors of groups you want the graph user to join
        :rtype: :class:`<GraphUser> <azure.devops.v5_1.graph.models.GraphUser>`
        """
        query_parameters = {}
        if group_descriptors is not None:
            group_descriptors = ",".join(group_descriptors)
            query_parameters['groupDescriptors'] = self._serialize.query('group_descriptors', group_descriptors, 'str')
        content = self._serialize.body(creation_context, 'GraphUserCreationContext')
        response = self._send(http_method='POST',
                              location_id='005e26ec-6b77-4e4f-a986-b3827bf241f5',
                              version='5.1-preview.1',
                              query_parameters=query_parameters,
                              content=content)
        return self._deserialize('GraphUser', response)