Python Metaprogramming

import types


class Klass:
    def __init__(self):
        self.x = 3


user_funcs = {
    'user_foo': '''
def user_foo(self):
    return 'foo' * self.x
''',
    'user_bar': '''
def user_bar(self):
    return 'bar' * self.x
'''
}

for n, f in user_funcs.items():
    exec(f)
    setattr(Klass, n, eval(n))

o = Klass()
for m in dir(o):
    if not m.startswith('user_'): continue
    print(f'dynamic call: {getattr(o, m)()}')

o2 = Klass()
o2.x = 4
print(f'o.user_bar(): {o.user_bar()}')
print(f'o2.user_bar(): {o2.user_bar()}')


def m(self):
    return 'hoge' * self.x


o2.user_bar = types.MethodType(m, o2)
print(f'o.user_bar(): {getattr(o, "user_bar")()}')
print(f're-def o2.user_bar(): {getattr(o2, "user_bar")()}')