def importer(name):
    """Handles strange import cases, like pxssh which might show
    up in eithr the package pexpect or pxssh.
    """
    if name == 'pxssh':
        try:
            import pxssh
        except ImportError:
            try:
                from pexpect import pxssh
            except ImportError:
                raise ImportError('pxssh not found!')
        return pxssh
    elif name == 'NeighborList':
        try:
            from ase.neighborlist import NeighborList
        except ImportError:
            from ase.calculators.neighborlist import NeighborList
        return NeighborList
