def determine_if_is_hmmdb(infp):
    """Return True if the given file is an HMM database (generated using
    hmmpress from the HMMer3 software package), and return False otherwise.
    """
    #if open(infp, 'r').read().startswith('HMMER3/f'):
    if open(infp, 'r').readline().startswith('HMMER3/f'):
        return True
    else:
        return False