code: def build_instructions(self, co):
          
          # FIXME: remove this when all subsidiary functions have been removed.
          # We should be able to get everything from the self.insts list.
          self.code = array('B', co.co_code)
  
          bytecode = Bytecode(co, self.opc)
          self.build_prev_op()
          self.insts = self.remove_extended_args(list(bytecode))
          self.lines = self.build_lines_data(co)
          self.offset2inst_index = {}
          for i, inst in enumerate(self.insts):
              self.offset2inst_index[inst.offset] = i
  
          return bytecode
docs: Create a list of instructions (a structured object rather than
          an array of bytes) and store that in self.insts