code: def find_nir_file_with_missing_depth(video_file_list, depth_file_list):
          "Remove all files without its own counterpart. Returns new lists of files"
          new_video_list = []
          new_depth_list = []
          for fname in video_file_list:
              try:
                  depth_file = Kinect.depth_file_for_nir_file(fname, depth_file_list)                
                  new_video_list.append(fname)
                  new_depth_list.append(depth_file)
              except IndexError: # Missing file
                  pass
                  
          # Purge bad files
          bad_nir = [f for f in video_file_list if f not in new_video_list]
          bad_depth = [f for f in depth_file_list if f not in new_depth_list]
          
          return (new_video_list, new_depth_list, bad_nir, bad_depthf find_nir_file_with_missing_depth(video_file_list, depth_file_list):
          "Remove all files without its own counterpart. Returns new lists of files"
          new_video_list = []
          new_depth_list = []
          for fname in video_file_list:
              try:
                  depth_file = Kinect.depth_file_for_nir_file(fname, depth_file_list)                
                  new_video_list.append(fname)
                  new_depth_list.append(depth_file)
              except IndexError: # Missing file
                  pass
                  
          # Purge bad files
          bad_nir = [f for f in video_file_list if f not in new_video_list]
          bad_depth = [f for f in depth_file_list if f not in new_depth_list]
          
          return (new_video_list, new_depth_list, bad_nir, bad_depth)
docs: Remove all files without its own counterpart. Returns new lists of files