old_contents: import os
  
  class FileIterator(object):
      """
      This FileIterator iterates over the paths contained in one or more directories.
      """
      def __init__(self, *paths):
          """
          @param paths: the file or directory paths.
          """
          self._paths = paths
      
      def __iter__(self):
          return self.next()
          
      def next(self):
          for f in self._paths:
              if os.path.isfile(f):
                  yield f
              elif os.path.isdir(f):
                  for root, dirs, paths in os.walk(f):
                      for f in paths:
                          path = os.path.join(root, f)
                          yield path
  
new_contents: import os
  
  class FileIterator(object):
      """
      This FileIterator iterates over the paths contained in one or more directories.
      """
      def __init__(self, *paths):
          """
          @param paths: the file or directory paths.
          """
          self._paths = paths
      
      def __iter__(self):
          return self.next()
          
      def next(self):
          for f in self._paths:
              if os.path.isfile(f):
                  yield f
              elif os.path.isdir(f):
                  for root, dirs, fnames in os.walk(f):
                      for fn in fnames:
                          path = os.path.join(root, fn)
                          yield path
  
subject: Rename paths variable to fnames.