code: def open(filename, frame='unspecified'):
          
          file_root, file_ext = os.path.splitext(filename)
          data = Image.load_data(filename)
          if file_ext.lower() in COLOR_IMAGE_EXTS:
              data = (data * (MAX_DEPTH / BINARY_IM_MAX_VAL)).astype(np.float32)
          return DepthImage(data, frame)
docs: Creates a DepthImage from a file.
  
          Parameters
          ----------
          filename : :obj:`str`
              The file to load the data from. Must be one of .png, .jpg,
              .npy, or .npz.
  
          frame : :obj:`str`
              A string representing the frame of reference in which the new image
              lies.
  
          Returns
          -------
          :obj:`DepthImage`
              The new depth image.