Create dynamic init function for base class based on annotations

dynamic_init.py

from types import FunctionType


class BaseClass:

    def __new__(cls, *args, **kwargs):
        # Creating a custom __init__ function
        params_string = ",".join(cls.params) # For init function arguments
        params_kwargs = ','.join([f"{i}={i}" for i in cls.params]) # Creating 
        k=f"""def __init__(self,{params_string}):\n\tBaseClass.__init__(self, {params_kwargs})
        """
        # print(k)
        init_code = compile(k, __file__, 'exec')
        __init__ = FunctionType(init_code.co_consts[0], globals(), "__init__")
        cls.__init__ = __init__
        instance = super(BaseClass, cls).__new__(cls)
        return instance


    def __init__(self, **kwargs):
        print("params", kwargs)



def param(name):
    def hello(custom_class):
        if not hasattr(custom_class, 'params'):
            custom_class.params = []
        custom_class.params.append(name)
        return custom_class
    return hello


@param(name="k")
@param(name="j")
class A(BaseClass):

    def __init__(self, **kwargs):
        pass

@param(name="l")
@param(name="m")
class M(BaseClass):

    def __init__(self, **kwargs):
        pass

A(j=3, k=5)
M(l=2, m=5)