does the actual work of indent_func

def _indent_decor(lbl):
    """
    does the actual work of indent_func
    """
    def closure_indent(func):
        if util_arg.TRACE:
            @ignores_exc_tb(outer_wrapper=False)
            #@wraps(func)
            def wrp_indent(*args, **kwargs):
                with util_print.Indenter(lbl):
                    print('    ...trace[in]')
                    ret = func(*args, **kwargs)
                    print('    ...trace[out]')
                    return ret
        else:
            @ignores_exc_tb(outer_wrapper=False)
            #@wraps(func)
            def wrp_indent(*args, **kwargs):
                with util_print.Indenter(lbl):
                    ret = func(*args, **kwargs)
                    return ret
        wrp_indent_ = ignores_exc_tb(wrp_indent)
        wrp_indent_ = preserve_sig(wrp_indent, func)
        return wrp_indent_
    return closure_indent