@staticmethod
def without_signature(data):
    """remove signature from string, if present"""
    if len(data) <= 10:
        return data
    firstline = data.splitlines()[0]
    if firstline != '-----BEGIN PGP SIGNED MESSAGE-----':
        return data
    text = ''
    for line in data.splitlines(True)[3:]:
        if line.rstrip() == '-----BEGIN PGP SIGNATURE-----':
            break
        text += line
    return text.rstrip()
