ADD:

AIC statistic added

etc/fitting/fitter.py

@@ -25,8 +25,8 @@ class DistributionSummary:
         Keyword arguments that were passed to fit() (fixed params, etc.).
     fit_result_params : tuple
         The actual fitted parameters returned by fit() (empty tuple until fit() is called).
-    statistic_method : str
-        GoF statistic identifier used in validate() (e.g. 'ad', 'ks').
+    statistic_method : object
+        GoF statistic identifier used in validate() (e.g. 'ad', 'ks' or a custom callable).
     test_result : object
         Result object from scipy.stats.goodness_of_fit; None until
         validate() is called. Exposes .statistic and .pvalue.
@@ -45,7 +45,7 @@ class DistributionSummary:
     args_fit_params: tuple = field(default_factory=tuple)
     kwds_fit_params: dict = field(default_factory=dict)
     fit_result_params: tuple = field(default_factory=tuple)
-    statistic_method: str = "ad"
+    statistic_method: object = "ad"
     test_result: object = None
 
     # ── convenience properties ────────────────────────────────────────────────