Encode the contents of the *input* file and write the resulting quoted-printable
data to the *output* file. *input* and *output* must be
- :term:`binary file objects <file object>`. *quotetabs*, a flag which controls
- whether to encode embedded spaces and tabs must be provideda and when true it
- encodes such embedded whitespace, and when false it leaves them unencoded.
+ :term:`binary file objects <file object>`. *quotetabs*, a
+ non-optional flag which controls whether to encode embedded spaces
+ and tabs; when true it encodes such embedded whitespace, and when
+ false it leaves them unencoded.
Note that spaces and tabs appearing at the end of lines are always encoded,
as per :rfc:`1521`. *header* is a flag which controls if spaces are encoded
as underscores as per :rfc:`1522`.