typing

src/ifcopenshell-python/ifcopenshell/express/__init__.py

@@ -16,9 +16,14 @@
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
 
+from __future__ import annotations
 import os
 import sys
 import subprocess
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    import schema_class
 
 d = os.path.abspath(os.path.dirname(__file__))
 sys.path.append(d)
@@ -30,8 +35,9 @@ if not os.path.exists(exp_parser_fn):
         subprocess.call([sys.executable, "bootstrap.py"], cwd=d, stdout=f)
 
 
-def parse(fn):
+def parse(fn: str) -> schema_class.SchemaClass:
     import express_parser
     import schema_class
+
     mapping = express_parser.parse(fn)
     return schema_class.SchemaClass(mapping, schema_class.LateBoundSchemaInstantiator).code