old_contents: """
  This module containes pure functions to parse and craft packets.
  """
  
  from ryu.lib.packet import packet
  from ryu.lib.packet import ethernet
  from ryu.lib.packet import arp
  from ryu.lib.packet import lldp
  
  def new_lldp():
      pass
  
  def new_arp():
      pass
  
  def parse_eth():
      pass
  
  def parse_lldp():
      pass
  
  def parse_arp():
      pass
  
new_contents: """
  This module containes pure functions to parse and craft packets.
  """
  
  from ryu.lib.packet import packet
  from ryu.lib.packet import ethernet
  from ryu.lib.packet import arp
  from ryu.lib.packet import lldp
  
  def create_lldp(dpid,port_no=DEFAULT_VALUE):
      '''
      Ryu.packet_lldp()
      '''
      pass
  
  def create_arp( dl_src,dl_dst,nl_src,nl_dst):
      '''
      => ARP()
      '''
      pass
  
  def parse_eth(data):
      pass
  
  def parse_lldp(decr,data):
      '''
      => (descr dictionary is built and descr is returned)
      
      '''
      pass
  
  def parse_arp(descr,data):
      '''
      Same as parse_lldp
      '''
      pass
  
  def parse(data):
      '''
      {"dl_type:","dl_src":}
      eth.header=()
      if parse.arp()
      elif parse_lldp()
      call parse_arp()
      '''
      pass
  
subject: Update packet.py