1from mypy.plugin import CallableType, CheckerPluginInterface, FunctionSigContext, Plugin
2from mypy.types import Instance, Type
3
4class FunctionSigPlugin(Plugin):
5    def get_function_signature_hook(self, fullname):
6        if fullname == '__main__.dynamic_signature':
7            return my_hook
8        return None
9
10def _str_to_int(api: CheckerPluginInterface, typ: Type) -> Type:
11    if isinstance(typ, Instance):
12        if typ.type.fullname == 'builtins.str':
13            return api.named_generic_type('builtins.int', [])
14        elif typ.args:
15            return typ.copy_modified(args=[_str_to_int(api, t) for t in typ.args])
16
17    return typ
18
19def my_hook(ctx: FunctionSigContext) -> CallableType:
20    return ctx.default_signature.copy_modified(
21        arg_types=[_str_to_int(ctx.api, t) for t in ctx.default_signature.arg_types],
22        ret_type=_str_to_int(ctx.api, ctx.default_signature.ret_type),
23    )
24
25def plugin(version):
26    return FunctionSigPlugin
27