diff --git a/operator_adm_export.py b/operator_adm_export.py
index ac8e166..b3545b9 100644
--- a/operator_adm_export.py
+++ b/operator_adm_export.py
@@ -1,33 +1,36 @@
 from bpy_extras.io_utils import ExportHelper
-from bpy.props import StringProperty, BoolProperty, EnumProperty, FloatProperty, IntProperty
+from bpy.props import StringProperty, BoolProperty, FloatProperty, IntProperty
 from bpy.types import Operator
 
 from .intern.generate_adm import generate_adm
 
-class ADMWaveExport(Operator, ExportHelper):
-    """Export a Broadcast-WAV audio file with each speaker encoded as an ADM object"""
-    bl_idname = "export.adm_wave_file"  # important since its how bpy.ops.import_test.some_data is constructed
-    bl_label = "Export ADM Wave File"
 
-    # ExportHelper mixin class uses this
+class ADMWaveExport(Operator, ExportHelper):
+    """
+    Export a Broadcast-WAV audio file with each speaker encoded as an ADM
+    object
+    """
+    bl_idname = "export.adm_wave_file"  # important since its how
+    bl_label = "Export ADM Wave File"
+    filepath: str
     filename_ext = ".wav"
 
-    filter_glob: StringProperty(
+    filter_glob = StringProperty(
         default="*.wav",
         options={'HIDDEN'},
         maxlen=255,  # Max internal buffer length, longer would be clamped.
     )
-    
-    room_size: FloatProperty(
+
+    room_size = FloatProperty(
         default=1.0,
         name="Room Size",
         description="Distance from the lens to the front room boundary",
         min=0.001,
-        step=1.,
+        step=1,
         unit='LENGTH'
     )
 
-    max_objects: IntProperty(
+    max_objects = IntProperty(
         name="Max Objects",
         description="Maximum number of object tracks to create",
         default=24,
@@ -35,13 +38,13 @@ class ADMWaveExport(Operator, ExportHelper):
         max=118
     )
 
-    create_bed: BoolProperty(
+    create_bed = BoolProperty(
         name="Create 7.1 Bed",
         description="Create a bed for all sounds not included on object tracks",
         default=False,
         options={'HIDDEN'}
     )
 
-    def execute(self, context):
-        return generate_adm(context, self.filepath, self.room_size, self.max_objects)
-
+    def execute(self, context) -> set:
+        return generate_adm(context, self.filepath, self.room_size,
+                            self.max_objects)