code: def _process_nested_expression(self, nested_expression) -> str:
          
          expression_is_list = isinstance(nested_expression, list)
          expression_size = len(nested_expression)
          if expression_is_list and expression_size == 1 and isinstance(nested_expression[0], list):
              return self._process_nested_expression(nested_expression[0])
          elements_are_leaves = [isinstance(element, str) for element in nested_expression]
          if all(elements_are_leaves):
              mapped_names = [self._map_name(name) for name in nested_expression]
          else:
              mapped_names = []
              for element, is_leaf in zip(nested_expression, elements_are_leaves):
                  if is_leaf:
                      mapped_names.append(self._map_name(element))
                  else:
                      mapped_names.append(self._process_nested_expression(element))
          if mapped_names[0] == "\\":
              # This means the predicate is lambda. NLTK wants the variable name to not be within parantheses.
              # Adding parentheses after the variable.
              arguments = [mapped_names[1]] + [f"({name})" for name in mapped_names[2:]]
          else:
              arguments = [f"({name})" for name in mapped_names[1:]]
          return f'({mapped_names[0]} {" ".join(arguments)})'
docs: ``nested_expression`` is the result of parsing a logical form in Lisp format.
          We process it recursively and return a string in the format that NLTK's ``LogicParser``
          would understand.