@classmethod
def FromRSAKeyPath(cls, rsa_key_path):
    """Create a :class:`PythonRSASigner` instance using the provided private key.

        Parameters
        ----------
        rsa_key_path : str
            The path to the private key; the public key must be ``rsa_key_path + '.pub'``.

        Returns
        -------
        PythonRSASigner
            A :class:`PythonRSASigner` with private key ``rsa_key_path`` and public key ``rsa_key_path + '.pub'``

        """
    with open(rsa_key_path + '.pub') as f:
        pub = f.read()
    with open(rsa_key_path) as f:
        priv = f.read()
    return cls(pub, priv)
