fix: account for multiple times wrapped functions (#476)

instructor/patch.py

@@ -467,9 +467,11 @@ def retry_sync(
 
 def is_async(func: Callable) -> bool:
     """Returns true if the callable is async, accounting for wrapped callables"""
-    return inspect.iscoroutinefunction(func) or (
-        hasattr(func, "__wrapped__") and inspect.iscoroutinefunction(func.__wrapped__)
-    )
+    is_coroutine = inspect.iscoroutinefunction(func)
+    while hasattr(func, "__wrapped__"):
+        func = func.__wrapped__
+        is_coroutine = is_coroutine or inspect.iscoroutinefunction(func)
+    return is_coroutine
 
 
 OVERRIDE_DOCS = """

tests/test_patch.py

@@ -39,6 +39,40 @@ def wrapped_function():
     assert is_async(wrapped_function) is True
 
 
+def test_is_async_returns_true_if_double_wrapped_function_is_async():
+    async def async_function():
+        pass
+
+    @functools.wraps(async_function)
+    def wrapped_function():
+        pass
+
+    @functools.wraps(wrapped_function)
+    def double_wrapped_function():
+        pass
+
+    assert is_async(double_wrapped_function) is True
+
+
+def test_is_async_returns_true_if_triple_wrapped_function_is_async():
+    async def async_function():
+        pass
+
+    @functools.wraps(async_function)
+    def wrapped_function():
+        pass
+
+    @functools.wraps(wrapped_function)
+    def double_wrapped_function():
+        pass
+
+    @functools.wraps(double_wrapped_function)
+    def triple_wrapped_function():
+        pass
+
+    assert is_async(triple_wrapped_function) is True
+
+
 def test_override_docs():
     assert (
         "response_model" in OVERRIDE_DOCS