Correction in number/float detection for floors, as it caused another crash in overnight rendering.

osmxml.py

@@ -205,6 +205,19 @@ class mstr_osmxml:
         return surface
     
 
+    # Again, a crash on number checking of levels.
+    # Short call for sanity check
+    def is_float(self, element: any) -> bool:
+        #If you expect None to be passed:
+        if element is None: 
+            return False
+        try:
+            float(element)
+            return True
+        except ValueError:
+            return False
+
+
     # Find the levels of a building (for shadow rendering)
     def find_building_levels(self, way_id):
         lvl = 2 # Standard if we don't find anything else
@@ -217,8 +230,9 @@ class mstr_osmxml:
                     a = tag.getAttribute("k")
                     v = tag.getAttribute("v")
                     if a == "building:levels":
-                        lvl = int(float(v)) # <- This blew layergen and maskgen at some buildings with 1.5 floors
-                        break
+                        if self.is_float(v) == True:
+                            lvl = int(float(v)) # <- This blew layergen and maskgen at some buildings with 1.5 floors
+                            break
         return lvl
     
     # Find minimum level of a building