code: def build(self):
          
          code = _upc.EDGE[:]
  
          for i, number in enumerate(self.upc[0:6]):
              code += _upc.CODES['L'][int(number)]
  
          code += _upc.MIDDLE
  
          for number in self.upc[6:]:
              code += _upc.CODES['R'][int(number)]
  
          code += _upc.EDGE
  
          return [code]
docs: Builds the barcode pattern from 'self.upc'
  
          :return: The pattern as string
          :rtype: String