code: def _access(self, subs, acc_type, val):
          
          if isinstance(subs, int):  
          # if subs is just an integer, take it to be an index value.
              subs = (subs,)
  
          if len(subs) == 0:
              raise For2PyError("Zero-length arrays currently not handled.")
  
          bounds = self._bounds
          sub_arr = self._values
          ndims = len(subs)
          for i in range(ndims):
              this_pos = self._posn(bounds[i], subs[i])
  
              if i == ndims-1:
                  if acc_type == _GET_:
                      return sub_arr[this_pos]
                  else:
                      sub_arr[this_pos] = val
              else:
                  sub_arr = sub_arr[this_pos]
docs: _access(subs, acc_type, val) accesses the array element specified by
             the tuple of subscript values, subs.  If acc_type == _GET_ it 
             returns the value of this element; else it sets this element to the
             value of the argument val.