header_source_parse(sourcelines) The email package calls this method with a list of strings, each string ending with the line separation characters found in the source being parsed. The first line includes the field header name and separator. All whitespace in the source is preserved. The method should return the (name, value) tuple that is to be stored in the Message to represent the parsed header. If an implementation wishes to retain compatibility with the existing email package policies,

remove(subelement) Removes subelement from the element. Unlike the find* methods this method compares elements based on the instance identity, not on tag value or contents.

Cookie.get_nonstandard_attr(name, default=None) If cookie has the named cookie-attribute, return its value. Otherwise, return default.

test.support.can_symlink() Return True if the OS supports symbolic links, False otherwise.

operator.is_not(a, b) Return a is not b. Tests object identity.

get_unixfrom() Return the message’s envelope header. Defaults to None if the envelope header was never set.

string.digits The string '0123456789'.

window.vline(ch, n) window.vline(y, x, ch, n) Display a vertical line starting at (y, x) with length n consisting of the character ch.

keys() Return a new view of the underlying mapping’s keys.

get_filename(failobj=None) Return the value of the filename parameter of the Content-Disposition header of the message. If the header does not have a filename parameter, this method falls back to looking for the name parameter on the Content-Type header. If neither is found, or the header is missing, then failobj is returned. The returned string will always be unquoted as per email.utils.unquote().