def _get_HL_chains(pdb_path):
    """Gets the heavy and light chain ID's from a chothia file from SAbDab"""
    # Get the line with the HCHAIN and LCHAIN
    hl_line = ''
    with open(pdb_path) as f:
        for line in f.readlines():
            if 'PAIRED_HL' in line:
                hl_line = line
                break
    if hl_line == '':
        return None

    words = hl_line.split(' ')
    h_chain = l_chain = None
    for word in words:
        if word.startswith('HCHAIN'):
            h_chain = word.split('=')[1]
        if word.startswith('LCHAIN'):
            l_chain = word.split('=')[1]
    return h_chain, l_chain