def METHOD_NAME(acceptors, indices):
    """Returns acceptors between atoms at given indices."""
    iset = set(indices)
    acceptors = [acceptor for acceptor in acceptors if acceptor[0] in iset and acceptor[1] in iset]
    if acceptors:
        newindices = np.zeros(indices.max()+1, int)
        newindices[indices] = np.arange(len(indices))
        return newindices[np.array(acceptors)]