diff --git a/src/blueapi/core/context.py b/src/blueapi/core/context.py
index cd3a0ede6..fd24f3ab4 100644
--- a/src/blueapi/core/context.py
+++ b/src/blueapi/core/context.py
@@ -108,10 +108,10 @@ def plan_2(...) -> MsgGenerator:
             # they are valid plans, unless there is an __all__ defined in the module,
             # in which case we only inspect objects listed there, regardless of their
             # original source module.
-            if (
+            if is_bluesky_plan_generator(obj) and (
                 hasattr(module, "__all__")
                 or is_function_sourced_from_module(obj, module)
-            ) and is_bluesky_plan_generator(obj):
+            ):
                 self.register_plan(obj)
 
     def with_device_module(self, module: ModuleType) -> None:
diff --git a/src/blueapi/utils/modules.py b/src/blueapi/utils/modules.py
index ca04237d3..932f86985 100644
--- a/src/blueapi/utils/modules.py
+++ b/src/blueapi/utils/modules.py
@@ -1,5 +1,5 @@
 import importlib
-from collections.abc import Iterable
+from collections.abc import Callable, Iterable
 from types import ModuleType
 from typing import Any
 
@@ -37,7 +37,9 @@ def get_named_subset(names: list[str]):
                 yield value
 
 
-def is_function_sourced_from_module(obj: Any, module: ModuleType) -> bool:
+def is_function_sourced_from_module(
+    obj: Callable[..., Any], module: ModuleType
+) -> bool:
     """
     Check if an object is originally from a particular module, useful to detect
     whether it actually comes from a nested import.
@@ -46,6 +48,4 @@ def is_function_sourced_from_module(obj: Any, module: ModuleType) -> bool:
         obj: Object to check
         module: Module to check against object
     """
-    return (
-        hasattr(obj, "__module__") and importlib.import_module(obj.__module__) is module
-    )
+    return importlib.import_module(obj.__module__) is module
diff --git a/tests/unit_tests/utils/functions_b.py b/tests/unit_tests/utils/functions_b.py
index 90c6714d6..78e72d560 100644
--- a/tests/unit_tests/utils/functions_b.py
+++ b/tests/unit_tests/utils/functions_b.py
@@ -5,6 +5,3 @@ def c(): ...
 
 
 def d(): ...
-
-
-e = 1
diff --git a/tests/unit_tests/utils/test_modules.py b/tests/unit_tests/utils/test_modules.py
index d9b47434b..5a0cf3bcf 100644
--- a/tests/unit_tests/utils/test_modules.py
+++ b/tests/unit_tests/utils/test_modules.py
@@ -15,14 +15,13 @@ def test_imports_everything_without_all():
 
 def test_source_is_in_module():
     module = import_module(".functions_b", package="tests.unit_tests.utils")
-    assert is_function_sourced_from_module(module.__dict__["c"], module)
+    c = module.__dict__["c"]
+    assert callable(c)
+    assert is_function_sourced_from_module(c, module)
 
 
 def test_source_is_not_in_module():
     module = import_module(".functions_b", package="tests.unit_tests.utils")
-    assert not is_function_sourced_from_module(module.__dict__["a"], module)
-
-
-def test_source_check_on_non_function():
-    module = import_module(".functions_b", package="tests.unit_tests.utils")
-    assert not is_function_sourced_from_module(module.__dict__["e"], module)
+    a = module.__dict__["a"]
+    assert callable(a)
+    assert not is_function_sourced_from_module(a, module)