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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 parse_logical_form(self, logical_form: str, remove_var_function: bool = True) -> Expression: """ Takes a logical form as a string, maps its tokens using the mapping and returns a parsed expression. Parameters logical_form : ``str`` Logical form to parse remove_var_function : ``bool`` (optional) ``var`` is a special function that some languages use within lambda functions to indicate the usage of a variable. If your language uses it, and you do not want to include it in the parsed expression, set this flag. You may want to do this if you are generating an action sequence from this parsed expression, because it is easier to let the decoder not produce this function due to the way constrained decoding is currently implemented. """

        if not logical_form.startswith("("):
            logical_form = f"({logical_form})"
        if remove_var_function:
            # Replace "(x)" with "x"
            logical_form = re.sub(r'\(([x-z])\)', r'\1', logical_form)
            # Replace "(var x)" with "(x)"
            logical_form = re.sub(r'\(var ([x-z])\)', r'(\1)', logical_form)
        parsed_lisp = semparse_util.lisp_to_nested_expression(logical_form)
        translated_string = self._process_nested_expression(parsed_lisp)
        type_signature = self.local_type_signatures.copy()
        type_signature.update(self.global_type_signatures)
        return self._logic_parser.parse(translated_string, signature=type_signature)