@@ -1,6 +1,7 @@
 use crate::{
     builtins::iter::PySequenceIterator,
     function::{IntoPyObject, IntoPyResult},
+    protocol::PySequence,
     PyObjectRef, PyObjectWrap, PyResult, PyValue, TryFromObject, TypeProtocol, VirtualMachine,
 };
 use std::borrow::Borrow;
@@ -120,11 +121,14 @@ impl TryFromObject for PyIter<PyObjectRef> {
                 )))
             }
         } else {
-            // TODO: __getitem__ method lookup must be replaced by sequence protocol checking
-            vm.get_method_or_type_error(iter_target.clone(), "__getitem__", || {
-                format!("'{}' object is not iterable", iter_target.class().name())
-            })?;
-            Ok(Self(PySequenceIterator::new(iter_target).into_object(vm)))
+            if PySequence::check(&iter_target, vm) {
+                Ok(Self(PySequenceIterator::new(iter_target).into_object(vm)))
+            } else {
+                Err(vm.new_type_error(format!(
+                    "'{}' object is not iterable",
+                    iter_target.class().name()
+                )))
+            }
         }
     }
 }
 
@@ -37,7 +37,13 @@ impl PySequence {
             return false;
         }
         cls.mro_find_map(|x| x.slots.as_sequence.load())
-            .map(|f| f(obj, vm).item.is_some())
+            .map(|f| {
+                // FIXME: we may avoid the check if we assume all the builtins
+                // implement fn item() for the sequence protocol
+                // all the python class must has __getitem__ if they ident as
+                // sequence protocol implemented
+                f(obj, vm).item.is_some()
+            })
             .unwrap_or(false)
     }
Original file line number	Diff line number	Diff line change
`@@ -37,7 +37,13 @@ impl PySequence {`
`37`	`37`	`return false;`
`38`	`38`	`}`
`39`	`39`	`cls.mro_find_map(\|x\| x.slots.as_sequence.load())`
`40`		`- .map(\|f\| f(obj, vm).item.is_some())`
	`40`	`+ .map(\|f\| {`
	`41`	`+ // FIXME: we may avoid the check if we assume all the builtins`
	`42`	`+ // implement fn item() for the sequence protocol`
	`43`	`+ // all the python class must has __getitem__ if they ident as`
	`44`	`+ // sequence protocol implemented`
	`45`	`+ f(obj, vm).item.is_some()`
	`46`	`+ })`
`41`	`47`	`.unwrap_or(false)`
`42`	`48`	`}`
`43`	`49`