def f(self, m):
if len(self.children) == <NUM_LIT:0>:<EOL><INDENT>return self._f(m)<EOL><DEDENT>elif len(self.children) == <NUM_LIT:1>:<EOL><INDENT>return self._f(m) and self.children[<NUM_LIT:0>].f(m)<EOL><DEDENT>else:<EOL><INDENT>raise Exception(<EOL>f"<STR_LIT>"<EOL>)<EOL><DEDENT>
The recursively composed version of filter function f.
By default, returns logical **conjunction** of operator and single
child operator