code: def read(self, filename, binary=False):
          
  
          self._raise_if_none()
          fn = path_join(self.path, filename)
  
          if binary:
              flags = 'br'
          else:
              flags = 'r'
  
          try:
              with open(fn, flags) as f:
                  return f.read()
          except IOError:
              return None
docs: Returns contents of given file with AppDir.
          If file doesn't exist, returns None.