As an example:

def some_method():
    errors = []
    resp1 = func1(..., errors)
    resp2 = func2(..., errors)
    if errors:
        print(f"Overall errors encountered: {errors}")
    else:
        print(f"Output={resp1+resp2}")

def func1(..., errors):
    # Do some processing
    if success:
        return response
    else:
        errors.append("Error occurred in func2")
        return

def func1(..., errors):
    # Do some processing
    if success:
        return response
    else:
        errors.append("Error occurred in func2")
        return

Should I rather initialize a local variable and return it so we get a tuple from the called functions 1 and 2. And then in some_method we extend the errors list.

What is a more pythonic way? And is passing lists a bad practice? Here it works in my favour because to each method, the errors list is passed as a reference so the original list gets appended to in each function called.