sage.
  It must contain one "()" named group ``<ids>`` containing the bug
  IDs separated by non-digit characters. It may also contain
  a named group ``<hours>`` with a floating-point number giving the
  hours worked on the bug. If no named groups are present, the first
  "()" group is assumed to contain the bug IDs, and work time is not
  updated. The default expression matches ``Bug 1234``, ``Bug no. 1234``,
  ``Bug number 1234``, ``Bugs 1234,5678``, ``Bug 1234 and 5678`` and
  variations thereof, followed by an hours number prefixed by ``h`` or
  ``hours``, e.g. ``hours 1.5``. Matching is case insensitive.