':param cert_chain_str_list: Must be a list of certificate strings,
where the first certificate to be validate
is in the beginning and the root certificate is last.
:param cert_str: The certificate to be validated.
:return:'

def verify_chain(self, cert_chain_str_list, cert_str):

    for tmp_cert_str in cert_chain_str_list:
        (valid, message) = self.verify(tmp_cert_str, cert_str)
        if (not valid):
            return (False, message)
        else:
            cert_str = tmp_cert_str
        return (True, 'Signed    certificate    is    valid    and    correctly    signed    by    CA    certificate.')
