diff --git a/src/ifcopenshell-python/ifcopenshell/__init__.py b/src/ifcopenshell-python/ifcopenshell/__init__.py
index e3f7fd0b25..a0662f24cc 100644
--- a/src/ifcopenshell-python/ifcopenshell/__init__.py
+++ b/src/ifcopenshell-python/ifcopenshell/__init__.py
@@ -135,7 +135,7 @@ def open(
 def open(path: Union[os.PathLike, str], format: Optional[str] = None, *, should_stream: Literal[True]) -> _stream: ...
 @overload
 def open(
-    path: Union[os.PathLike, str], format: Optional[str] = None, *, should_stream: bool
+    path: Union[os.PathLike, str], format: Optional[str] = None, *, should_stream: bool = False, readonly: bool = False
 ) -> Union[_file, sqlite, _stream]: ...
 def open(
     path: Union[os.PathLike, str], format: Optional[str] = None, should_stream: bool = False, readonly: bool = False
diff --git a/src/ifcopenshell-python/test/typing_tests.py b/src/ifcopenshell-python/test/typing_tests.py
new file mode 100644
index 0000000000..5e2a14fd39
--- /dev/null
+++ b/src/ifcopenshell-python/test/typing_tests.py
@@ -0,0 +1,39 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2021 Thomas Krijnen <thomas@aecgeeks.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# IfcOpenShell is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+"""Typing tests for ifcopenshell.
+
+This file should produce no warnings from type checker (currently pyright).
+Those tests are not automatically checked and just there to make sure overloads are making sense.
+"""
+
+
+import ifcopenshell
+from typing import assert_type, Union
+
+
+def ifcopenshell_open_test(str_: str, bool_: bool):
+    ifc_file = ifcopenshell.open(str_)
+    assert_type(ifc_file, Union[ifcopenshell.file, ifcopenshell.sqlite])
+
+    ifc_file = ifcopenshell.open(str_, should_stream=bool_)
+    assert_type(ifc_file, Union[ifcopenshell.file, ifcopenshell.sqlite, ifcopenshell.stream])
+
+    ifc_file = ifcopenshell.open(str_, should_stream=True)
+    assert_type(ifc_file, ifcopenshell.stream)
+
+    ifc_file = ifcopenshell.open(str_, readonly=True)