Returns current utcoffset for a timezone. Uses
    DEFAULT_LOCAL_TZ by default. That value can be
    changed at runtime using the func below.

def current_offset(local_tz=None):
    """
    Returns current utcoffset for a timezone. Uses
    DEFAULT_LOCAL_TZ by default. That value can be
    changed at runtime using the func below.
    """
    if local_tz is None:
        local_tz = DEFAULT_LOCAL_TZ
    dt = local_tz.localize(datetime.now())
    return dt.utcoffset()