def add_edge_attrs(graph, s, t, attrs):
    """Add attributes of an edge in a graph.

    Parameters
    ----------
    graph : regraph.Graph
    s : hashable, source node id.
    t : hashable, target node id.
    attrs : dict
        Dictionary with attributes to remove.

    Raises
    ------
    GraphError
        If an edge between `s` and `t` does not exist.
    """
    graph.add_edge_attrs(s, t, attrs)
