def atom_pairs_to_cpptraj_atommask(atom_pairs):
    """
    Notes: not validate yet

    Parameters
    ----------
    atom_pairs : 2D array-like

    Returns
    -------
    1D array of cpptraj mask

    Examples
    >>> atom_pairs_to_cpptraj_atommask([[0, 3], [5, 6]])
    ['@1 @4', '@6 @7']
    """
    import numpy as np
    if not isinstance(atom_pairs, np.ndarray):
        atom_pairs = np.asarray(atom_pairs)
    atom_pairs = (atom_pairs + 1).astype('str')
    out = []
    for idx, pair in enumerate(atom_pairs):
        out.append(' '.join(('@' + pair[0], '@' + pair[1])))
    return out
