ENH: Add support for IndirectObject.__contains__ (#3155)

Closes #3154.

pypdf/generic/_base.py

@@ -392,6 +392,9 @@ def __getitem__(self, key: Any) -> Any:
         # items should be extracted from pointed Object
         return self._get_object_with_check()[key]  # type: ignore
 
+    def __contains__(self, key: Any) -> bool:
+        return key in self._get_object_with_check()  # type: ignore
+
     def __float__(self) -> str:
         # in this case we are looking for the pointed data
         return self.get_object().__float__()  # type: ignore

tests/test_generic.py

@@ -1032,6 +1032,13 @@ def test_indirect_object_page_dimensions():
     assert mediabox == RectangleObject((0, 0, 792, 612))
 
 
+def test_indirect_object_contains():
+    writer = PdfWriter()
+    indirect_object = IndirectObject(1, 0, writer)
+    assert "foo" not in indirect_object
+    assert "/Producer" in indirect_object
+
+
 def test_array_operators():
     a = ArrayObject(
         [