title: python __metaclass__ doesn’t work
body: <pre><code>   class UpperAttrMetaClass(type):
      def __new__(upperattr_metaclass, future_class_name, future_class_parents, future_class_attr):
          attrs = ((name, value) for name, value in future_class_attr.items() if not name.startswith('__'))
          uppercase_attr = dict((name.upper(), value) for name, value in attrs)
          return type.__new__(upperattr_metaclass,future_class_name, future_class_parents, uppercase_attr)
  
  
  
  class boo(object):
      __metaclass__ = UpperAttrMetaClass
      bar = 'birr'
  
  
  print(hasattr(boo,'BAR'))
  </code></pre>
  
  <p>my goal is to transform the attribute named 'bar' of the class boo into uppercase 'BAR' using <strong>metaclass</strong>,but the program's result is 'False' showing that it doesn't work ,i am confused.</p>