add robust ci to str

Author: SvenKlaassen

doubleml/irm/iivm.py

@@ -197,6 +197,23 @@ def __init__(
         self.subgroups = subgroups
         self._external_predictions_implemented = True
 
+    def __str__(self):
+        parent_str = super().__str__()
+
+        # add robust confset
+        if self.framework is None:
+            confset_str = ""
+        else:
+            confset = self.robust_confset()
+            formatted_confset = ", ".join([f"[{lower:.4f}, {upper:.4f}]" for lower, upper in confset])
+            confset_str = (
+                "\n\n--------------- Additional Information ----------------\n"
+                + f"Robust Confidence Set: {formatted_confset}\n"
+            )
+
+        res = parent_str + confset_str
+        return res
+
     @property
     def normalize_ipw(self):
         """

doubleml/irm/tests/test_iivm_unif_confset.py

@@ -76,6 +76,11 @@ def test_exceptions_robust_confset():
     with pytest.raises(ValueError, match=msg):
         dml_iivm_obj.robust_confset()
 
+    # Check if str representation of the object is working
+    str_repr = str(dml_iivm_obj)
+    assert isinstance(str_repr, str)
+    assert "Robust" not in str_repr
+
     # Fit the model
     dml_iivm_obj.fit()
 
@@ -86,3 +91,8 @@ def test_exceptions_robust_confset():
     msg = r"The confidence level must be in \(0,1\). 1.5 was passed."
     with pytest.raises(ValueError, match=msg):
         dml_iivm_obj.robust_confset(level=1.5)
+
+    # Check if str representation of the object is working
+    str_repr = str(dml_iivm_obj)
+    assert isinstance(str_repr, str)
+    assert "Robust Confidence Set" in str_repr