text: from __future__ import absolute_import
  
  from .field import Field
  
  class padding(Field):
      '''Arbitrary data. For consistency, a struct which unpacks padding,
      then changes non-padding fields and repacks will use the same byte
      values as it originally read. Defaults to `length` null bytes.
      '''
      def __init__(self, length):
          super(padding, self).__init__()
          self.length = length
          self.default = b'\0'*length
  
      def pack(self, value, struct):
          return value+b'\0'*(self.length-len(value))
  
      def unpack(self, reader, struct):
          return reader.read(self.length)
  