Python functions locked without setup() function (see https://twitter.com/randal_olson/status/599610510795874304)

function_lock.py

from __future__ import print_function
from functools import wraps

class UnitialisedFunctionCallException(Exception):
    pass

def setup_function(function_):

    @wraps(function_)
    def setter(self, *args, **kwargs):
        try:
            ans = function_(self, *args, **kwargs)
        except:
            pass
        else:
            self.__initialised__ = True

        return ans

    return setter

def needs_setup(function_):

        @wraps(function_)
        def setter(self, *args, **kwargs):

            try:
                initialised = self.__initialised__
            except AttributeError:
                initialised = False

            if not initialised:
                raise UnitialisedFunctionCallException(
                    'Function {!r} called without appropriate initialisation' \
                        .format(function_))

            return function_(self, *args, **kwargs)

        return setter

class A(object):

    @setup_function
    def setup(self, some_arg):
        self.some_arg = some_arg

    @needs_setup
    def print_some_arg(self, parameter):
        print(self.some_arg, parameter)

# >>> a = A()
# >>> a.print_some_arg('test')
#     UnitialisedFunctionCallException: Function <function print_some_arg at 0x10d0ca5f0> called without appropriate initialisation
# >>> a.setup('derp')
# >>> a.print_some_arg('test')
#     derp test