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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _process_group(input_group, required_group, groupname, append_subgroups=None):
 """ Process one group from the input yaml. Ensure it has the required entries. If there is a subgroup that should be processed and then appended to the rest of the subgroups in that group, handle it accordingly. :param dict input_group: The dict of values of the input group :param dict required_group: The dict of required values for the input group :param str groupname: The name of the group being processed :param list append_subgroups: list of subgroups to append to each, other subgroup in this group :return: processed dict of entries for the group :rtype: dict """

    if append_subgroups is None:
        append_subgroups = []
    tool_options = {}
    for key in input_group:
        _ensure_set_contains(input_group[key], required_group.get(key, {}), groupname + '::' + key)
        if key in append_subgroups:
            continue
        else:
            tool_options[key] = input_group[key]
    for key in input_group:
        if key in append_subgroups:
            continue
        else:
            for yek in append_subgroups:
                tool_options[key].update(input_group[yek])
    return tool_options