def get_edges(source_label, target_label, edge_label):
    """Generate query for getting all the edges of the graph.

    Parameters
    ----------
    source_label : optional
        Label of the source nodes to match
    target_label : optional
        Label of the target nodes to match
    edge_label : iterable, optional
        Label of the edges to match
    """
    query = 'MATCH (n:{})-[r:{}]->(m:{})\nRETURN n.id, m.id\n'.format(
        source_label, edge_label, target_label)
    return query
