code: def open(self, value, nt=None, wrap=None, unwrap=None):
          
  
          self._wrap = wrap or (nt and nt.wrap) or self._wrap
          self._unwrap = unwrap or (nt and nt.unwrap) or self._unwrap
  
          _SharedPV.open(self, self._wrap(value))
docs: Mark the PV as opened an provide its initial value.
          This initial value is later updated with post().
  
          :param value:  A Value, or appropriate object (see nt= and wrap= of the constructor).
  
          Any clients which have begun connecting which began connecting while
          this PV was in the close'd state will complete connecting.
  
          Only those fields of the value which are marked as changed will be stored.