Error log as applicative function

gistfile1.py

class MyClass:
    def __init__(self):
        self.errors = []
        self.warnings = []

    def apply(self, function, *args):
        result, self.errors, self.warnings = function(*args, errors=self.errors, warnings=self.warnings)
        return result

    def applicative_functor_style(self, ast):
        a = self.apply(f_a, ast)
        b = self.apply(f_b, a)
    
    def old_way(self, ast):
        a, self.errors, self.warnings = f_a(ast, self.errors, self.warnings)
        b, self.errors, self.warnings = f_b(a, self.errors, self.warnings)

def f_a(ast, errors, warnings):
    # compute
    errors.append('Error #1')
    # compute
    warnings.append('Warning #1')
    # compute
    result = #...
    
    return (result, errors, warnings)