'Create a CloudFrontSigner.
:type key_id: str
:param key_id: The CloudFront Key Pair ID
:type rsa_signer: callable
:param rsa_signer: An RSA signer.
Its only input parameter will be the message to be signed,
and its output will be the signed content as a binary string.
The hash algorithm needed by CloudFront is SHA-1.'

def __init__(self, key_id, rsa_signer):

    self.key_id = key_id
    self.rsa_signer = rsa_signer
