Add 'contains' method to PyAny

CHANGELOG.md

@@ -28,6 +28,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Accept paths in `wrap_pyfunction` and `wrap_pymodule`. [#2081](https://github.com/PyO3/pyo3/pull/2081)
 - Add check for correct number of arguments on magic methods. [#2083](https://github.com/PyO3/pyo3/pull/2083)
 - `wrap_pyfunction!` can now wrap a `#[pyfunction]` which is implemented in a different Rust module or crate. [#2091](https://github.com/PyO3/pyo3/pull/2091)
+- Add `PyAny::contains` method (`in` operator for `PyAny`). [#2115](https://github.com/PyO3/pyo3/pull/2115)
 
 ### Changed
 

src/types/any.rs

@@ -682,6 +682,24 @@ impl PyAny {
         self.is_instance(T::type_object(self.py()))
     }
 
+    /// Determines if self contains `value`.
+    ///
+    /// This is equivalent to the Python expression `value in self`.
+    #[inline]
+    pub fn contains<V>(&self, value: V) -> PyResult<bool>
+    where
+        V: ToBorrowedObject,
+    {
+        let r = value.with_borrowed_ptr(self.py(), |ptr| unsafe {
+            ffi::PySequence_Contains(self.as_ptr(), ptr)
+        });
+        match r {
+            0 => Ok(false),
+            1 => Ok(true),
+            _ => Err(PyErr::fetch(self.py())),
+        }
+    }
+
     /// Returns a GIL marker constrained to the lifetime of this type.
     #[inline]
     pub fn py(&self) -> Python<'_> {
@@ -797,4 +815,26 @@ class SimpleClass:
             assert!(l.is_instance(PyList::type_object(py)).unwrap());
         });
     }
+
+    #[test]
+    fn test_any_contains() {
+        Python::with_gil(|py| {
+            let v: Vec<i32> = vec![1, 1, 2, 3, 5, 8];
+            let ob = v.to_object(py).into_ref(py);
+
+            let bad_needle = 7i32.to_object(py);
+            assert!(!ob.contains(&bad_needle).unwrap());
+
+            let good_needle = 8i32.to_object(py);
+            assert!(ob.contains(&good_needle).unwrap());
+
+            let type_coerced_needle = 8f32.to_object(py);
+            assert!(ob.contains(&type_coerced_needle).unwrap());
+
+            let n: u32 = 42;
+            let bad_haystack = n.to_object(py).into_ref(py);
+            let irrelevant_needle = 0i32.to_object(py);
+            assert!(bad_haystack.contains(&irrelevant_needle).is_err());
+        });
+    }
 }