code: def get_filename(self):
          ''' Return the source filename of the current Stim. '''
          if self.filename is None or not os.path.exists(self.filename):
              tf = tempfile.mktemp() + self._default_file_extension
              self.save(tf)
              yield tf
              os.remove(tf)
          else:
              yield self.filenamf get_filename(self):
          ''' Return the source filename of the current Stim. '''
          if self.filename is None or not os.path.exists(self.filename):
              tf = tempfile.mktemp() + self._default_file_extension
              self.save(tf)
              yield tf
              os.remove(tf)
          else:
              yield self.filename
docs: Return the source filename of the current Stim.