:param systemId: ID of Cluster
        :param snapshotGroupId: ID of snapshot group ID to be removed
        
        
        /api/instances/System::{id}/action/removeConsistencyGroupSnapshots
        type: POST
        Required:
            snapGroupId
        Return:
            numberOfVolumes - number of volumes that were removed because of this operation

def delete_snapshot(self, systemId, snapshotGroupId):
        """
        :param systemId: ID of Cluster
        :param snapshotGroupId: ID of snapshot group ID to be removed
        
        
        /api/instances/System::{id}/action/removeConsistencyGroupSnapshots
        type: POST
        Required:
            snapGroupId
        Return:
            numberOfVolumes - number of volumes that were removed because of this operation
        
        """
        #try:
        consistencyGroupIdDict = {'snapGroupId':snapshotGroupId}
        self.conn.connection._check_login()
        response = self.conn.connection._do_post("{}/{}{}/{}".format(self.conn.connection._api_url, "instances/System::", systemId, 'action/removeConsistencyGroupSnapshots'), json=consistencyGroupIdDict)
        #except:
        #    raise RuntimeError("delete_snapshot() - Error communicating wit ScaleIO gateway")
        return response