def METHOD_NAME(header):
    """RFC 2616 (HTTP 1.1) Range header parsing.
    Convert a range header to a list of slice indexes, returned as (start, end)
    tuples. If no end was given, end is None. Note that the RFC specifies the
    end offset to be inclusive, we return python convention indexes, where the
    end is exclusive. Syntactically incorrect headers are to be ignored, so if
    we encounter one we return None.
    """
    ranges = []
    add = ranges.append
    # First, clean out *all* whitespace. This is slightly more tolerant
    # than the spec asks for, but hey, it makes this function much easier.
    header = WHITESPACE.sub('', header)
    # A range header only can specify a byte range
    try:
        spec, sets = header.split('=')
    except ValueError:
        return None
    if spec != 'bytes':
        return None
    # The sets are delimited by commas.
    sets = sets.split(',')
    # Filter out empty values, things like ',,' are allowed in the spec
    sets = [_set for _set in sets if _set]
    # We need at least one set
    if not sets:
        return None
    for set in sets:
        try:
            start, end = set.split('-')
        except ValueError:
            return None
        # Catch empty sets
        if not start and not end:
            return None
        # Convert to integers or None (which will raise errors if
        # non-integers were used (which is what we want)).
        try:
            if start == '':
                start = None
            else:
                start = int(start)
            if end == '':
                end = None
            else:
                end = int(end)
        except ValueError:
            return None
        # Special case: No start means the suffix format was used, which
        # means the end value is actually a negative start value.
        # Convert this by making it absolute.
        # A -0 range is converted to sys.maxsize, which will result in a
        # Unsatisfiable response if no other ranges can by satisfied either.
        if start is None:
            start, end = -end, None
            if not start:
                start = sys.maxsize
        elif end is not None:
            end = end + 1  # Make the end of the range exclusive
        if end is not None and end <= start:
            return None
        # And store
        add((start, end))
    return ranges