code: def read(cls, f):
      
      header = WETHeader.read(f)
      if header is None:
        # EOF
        return None
      content = f.read(header.length)
  
      # Consume empty separators
      f.readline()
      f.readline()
  
      return cls(header.url, content)
docs: Read WETRecord from file. Records end with 2 blank lines.