code: def do_format(self, format):
          
          if (format is not None):
              raise IIIFError(code=415, parameter="format",
                              text="Null manipulator does not support specification of output format.")
          #
          if (self.outfile is None):
              self.outfile = self.srcfile
          else:
              try:
                  shutil.copyfile(self.srcfile, self.outfile)
              except IOError as e:
                  raise IIIFError(code=500,
                                  text="Failed to copy file (%s)." % (str(e)))
          self.mime_type = None
docs: Null implementation of format selection.
  
          This is the last step, this null implementation does not accept any
          specification of a format because we don't even know what the input
          format is.