Update screenshot.py

screenshot.py

@@ -31,4 +31,7 @@ def create_ss(graph):
             driver.set_window_size(int(width), int(height))
             obj = driver.find_element(By.ID, "chart_box")            
             screenshot = obj.screenshot(f'{uid}-tmp.png')
-    return(f'{uid}-tmp.png')  
+            return(f'{uid}-tmp.png')  
+        except Exception as e:
+            print(e)
+            return None