code: def remove(src, rel, dst):
      
      smt = 'DELETE FROM %s' % rel
      queries = []
      params = []
  
      if src is not None:
          queries.append('src = ?')
          params.append(src)
  
      if dst is not None:
          queries.append('dst = ?')
          params.append(dst)
  
      if not queries:
          return smt, params
      smt = '%s WHERE %s' % (smt, ' AND '.join(queries))
      return smt, params
docs: Returns an SQL statement that removes edges from
      the SQL backing store. Either `src` or `dst` may
      be specified, even both.
  
      :param src: The source node.
      :param rel: The relation.
      :param dst: The destination node.