Create util to instanciate objects and validate arguments (#164)

src/aequitas/flow/methods/preprocessing/label_flipping.py

@@ -1,9 +1,8 @@
 from .preprocessing import PreProcessing
 
 from ...utils import create_logger
-from ...utils.imports import import_object
+from ...utils.imports import instantiate_object
 
-import inspect
 import pandas as pd
 import math
 from typing import Optional, Tuple, Literal, Union, Callable
@@ -104,26 +103,8 @@ def __init__(
 
         self.bagging_max_samples = bagging_max_samples
 
-        if isinstance(bagging_base_estimator, str):
-            bagging_base_estimator = import_object(bagging_base_estimator)
-        signature = inspect.signature(bagging_base_estimator)
-        if (
-            signature.parameters[list(signature.parameters.keys())[-1]].kind
-            == inspect.Parameter.VAR_KEYWORD
-        ):
-            args = (
-                base_estimator_args  # Estimator takes **kwargs, so all args are valid
-            )
-        else:
-            args = {
-                arg: value
-                for arg, value in base_estimator_args.items()
-                if arg in signature.parameters
-            }
-        self.bagging_base_estimator = bagging_base_estimator(**args)
-        self.logger.info(
-            f"Created base estimator {self.bagging_base_estimator} with params {args}, "
-            f"discarded args:{list(set(base_estimator_args.keys()) - set(args.keys()))}"
+        self.bagging_base_estimator = instantiate_object(
+            bagging_base_estimator, **base_estimator_args
         )
         self.bagging_n_estimators = bagging_n_estimators
 
@@ -317,7 +298,7 @@ def transform(
             The transformed input, X, y, and s.
         """
         super().transform(X, y, s)
-        
+
         self.logger.info("Transforming data with LabelFlipping.")
 
         if s is None and self.fair_ordering:

src/aequitas/flow/utils/imports.py

@@ -1,5 +1,6 @@
 import importlib
 from typing import Callable, Union
+import inspect
 
 
 def import_object(import_path: str) -> Union[object, Callable]:
@@ -20,7 +21,37 @@ def import_object(import_path: str) -> Union[object, Callable]:
     """
     separator_idx = import_path.rindex(".")
     module_path = import_path[:separator_idx]
-    obj_name = import_path[separator_idx + 1 :]
+    obj_name = import_path[separator_idx + 1:]
 
     module = importlib.import_module(module_path)
     return getattr(module, obj_name)
+
+
+def instantiate_object(class_object: Union[str, Callable], **kwargs) -> object:
+    """Instantiates an object by their classpath.
+
+    Parameters
+    ----------
+    class_object : Union[str, Callable]
+        The classpath of the object to instantiate.
+    **kwargs
+        The keyword arguments to pass to the class constructor.
+
+    Returns
+    -------
+    object
+        The instantiated object.
+    """
+
+    class_object = import_object(class_object)
+    signature = inspect.signature(class_object)
+    if (
+        signature.parameters[list(signature.parameters.keys())[-1]].kind
+        == inspect.Parameter.VAR_KEYWORD
+    ):
+        args = kwargs
+    else:
+        args = {
+            arg: value for arg, value in kwargs.items() if arg in signature.parameters
+        }
+    return class_object(**args)