def remove_edge(graph, s, t):
    """Remove edge from a graph.

    Parameters
    ----------
    graph : regraph.Graph
    s : hashable, source node id.
    t : hashable, target node id.

    Raises
    ------
    GraphError
        If edge between `s` and `t` does not exist.

    """
    graph.remove_edge(s, t)
