def auth_ec2(self, pkcs7, nonce=None, role=None, use_token=True, mount_point='aws-ec2'):
        """POST /auth/<mount point>/login

        :param pkcs7: PKCS#7 version of an AWS Instance Identity Document from the EC2 Metadata Service.
        :type pkcs7: str.
        :param nonce: Optional nonce returned as part of the original authentication request. Not required if the backend
            has "allow_instance_migration" or "disallow_reauthentication" options turned on.
        :type nonce: str.
        :param role: Identifier for the AWS auth backend role being requested.
        :type role: str.
        :param use_token: If True, uses the token in the response received from the auth request to set the "token"
            attribute on the current Client class instance.
        :type use_token: bool.
        :param mount_point: The "path" the AWS auth backend was mounted on. Vault currently defaults to "aws". "aws-ec2"
            is the default argument for backwards comparability within this module.
        :type mount_point: str.
        :return: parsed JSON response from the auth POST request
        :rtype: dict.

        """
        params = {'pkcs7': pkcs7}
        if nonce:
            params['nonce'] = nonce
        if role:
            params['role'] = role

        return self.login('/v1/auth/{0}/login'.format(mount_point), json=params, use_token=use_token)
POST /auth/<mount point>/login

        :param pkcs7: PKCS#7 version of an AWS Instance Identity Document from the EC2 Metadata Service.
        :type pkcs7: str.
        :param nonce: Optional nonce returned as part of the original authentication request. Not required if the backend
            has "allow_instance_migration" or "disallow_reauthentication" options turned on.
        :type nonce: str.
        :param role: Identifier for the AWS auth backend role being requested.
        :type role: str.
        :param use_token: If True, uses the token in the response received from the auth request to set the "token"
            attribute on the current Client class instance.
        :type use_token: bool.
        :param mount_point: The "path" the AWS auth backend was mounted on. Vault currently defaults to "aws". "aws-ec2"
            is the default argument for backwards comparability within this module.
        :type mount_point: str.
        :return: parsed JSON response from the auth POST request
        :rtype: dict.