Converts the given ETree tree from XHTML to HTML in-place. Raises ValueError if a non-XHTML namespace is encountered.
Take the @class attribute of node, split it at spaces, put it into a set, add cls to the set and re-join the set with spaces.
If fileref is a file name or a file like with associated fileno which points to an actual file, return the date of last modification stored in the filesystem, None otherwise.
By default, the times are truncated to full seconds. If you need the floating point part of the times (if supported by the platform), pass True to float_times.
Return a tuple (useragent, version), where useragent is one of:
version will be either the version number of the user agent or None if the version could not be determined reliably. The version number is represented as a floating point value.
Parse a date like returned with isoformat(), but with a trailing Z to indicate the UTC timezone.