code: def getElementsByClassName(self, className):
          '''
              getElementsByClassName - Get elements within this collection containing a specific class name
  
              @param className - A single class name
  
              @return - TagCollection of unique elements within this collection tagged with a specific class name
          '''
          ret = TagCollection()
          if len(self) == 0:
              return ret
          _cmpFunc = lambda tag : tag.hasClass(className)
          for tag in self:
              TagCollection._subset(ret, _cmpFunc, tag)
          
          return ref getElementsByClassName(self, className):
          '''
              getElementsByClassName - Get elements within this collection containing a specific class name
  
              @param className - A single class name
  
              @return - TagCollection of unique elements within this collection tagged with a specific class name
          '''
          ret = TagCollection()
          if len(self) == 0:
              return ret
          _cmpFunc = lambda tag : tag.hasClass(className)
          for tag in self:
              TagCollection._subset(ret, _cmpFunc, tag)
          
          return ret
docs: getElementsByClassName - Get elements within this collection containing a specific class name
  
              @param className - A single class name
  
              @return - TagCollection of unique elements within this collection tagged with a specific class name