Sign function incorrectly strips one trailing CRLF

[Avamander]

When trying to generate a valid signature according to RFC3156 I stumbled upon the fact that the last \r\n of the bytes given to sign are stripped.

Example:

text = "example text\r\n".encode()
signature = sign(text)
assert verify(signature, text) == True

> AssertionError

Workaround:

text = "example text\r\n".encode()
signature = sign(text + "\r\n".encode())
assert verify(signature, text) == True