code: def previous(self):
      if self.pos == 0:
          return None
      return self.seq[self.pos - 1]
  
imports: import sys
  from Cython.Tempita.compat3 import basestring_
label_desc: Use image node_id 7 for calling the loop_pos obj's underlying member method code with example usage: obj.previous() and returns: self, None