Invalid email assumed to be valid AKA Why are untrimmed emails considered valid emails?

[TimeBomb]

Due to strip() invoked on address at

flanker/flanker/addresslib/address.py

Line 112 in 57701a6

parse_rs = parser.parse(address.strip(), lexer=lexer.clone())

any address passed to is_email that contains trailing or leading whitespace is considered a valid email, making the occasionally incorrect assumption that the consumer will strip whitespace from the presumed-valid email.
This can cause issues where an invalid email, i.e. one containing leading/trailing whitespace, is assumed to be valid.