old_contents: from Client import Client
  from Server import Server
  from rammbock.Interface import VirtualInterface, PhysicalInterface
  
  class Rammbock(object):
  
      def __init__(self):
              self.interfaces = {}
              self._client = Client()
              self._server = Server(self.interfaces)
  
      def create_virtual_interface(self, if_alias, ifname, ip_address, netmask):
          print "create_virtual_interface " + if_alias
          if if_alias in self.interfaces and  self.interfaces[if_alias].ifUp:
              raise Exception('Interface "%s" already exists' % if_alias)
          self.interfaces[if_alias] = VirtualInterface(if_alias, ifname, ip_address, netmask)
  
      def use_interface(self, if_alias, ifname, ip_address=None, netmask=None):
          print "use_interface " + if_alias
          self.interfaces[if_alias] = PhysicalInterface(if_alias, ifname, ip_address, netmask)
  
      def is_interface_up(self, ifname):
          self.interfaces
          print "is_interface_up " + ifname
          return self.interfaces[ifname].check_interface()
  
      def delete_interface(self, ifname):
          self.interfaces
          print "delete_interface " + ifname
          return self.interfaces[ifname].del_interface()
  
      def start_server(self, if_alias, port):
          self._server.server_startup(if_alias, port)
  
      def connect_to_server(self, host, port):
          self._client.establish_connection_to_server(host, port)
  
      def close_server(self):
          self._server.close_server()
  
      def close_client(self):
          self._client.close_client()
  
      def client_send_packet_over_udp(self, packet): 
          self._client.send_packet_over_udp(packet)
  
      def server_receive_packet_over_udp(self):
          return self._server.receive_packet_over_udp()
  
      def server_send_packet_over_udp(self, packet): 
          self._server.send_packet_over_udp(packet)
  
      def client_receive_packet_over_udp(self):
          return self._client.receive_packet_over_udp()
  
new_contents: from Client import Client
  from Server import Server
  from rammbock.Interface import VirtualInterface, PhysicalInterface
  
  class Rammbock(object):
  
      def __init__(self):
              self.interfaces = {}
              self._client = Client()
              self._server = Server(self.interfaces)
  
      def create_virtual_interface(self, if_alias, ifname, ip_address, netmask):
          print "create_virtual_interface " + if_alias
          if if_alias in self.interfaces and  self.interfaces[if_alias].ifUp:
              raise Exception('Interface "%s" already exists' % if_alias)
          self.interfaces[if_alias] = VirtualInterface(if_alias, ifname, ip_address, netmask)
  
      def use_interface(self, if_alias, ifname, ip_address=None, netmask=None):
          print "use_interface " + if_alias
          self.interfaces[if_alias] = PhysicalInterface(if_alias, ifname, ip_address, netmask)
  
      def is_interface_up(self, ifname):
          print "is_interface_up " + ifname
          return self.interfaces[ifname].check_interface()
  
      def delete_interface(self, ifname):
          print "delete_interface " + ifname
          return self.interfaces[ifname].del_interface()
  
      def start_server(self, if_alias, port):
          self._server.server_startup(if_alias, port)
  
      def connect_to_server(self, host, port):
          self._client.establish_connection_to_server(host, port)
  
      def close_server(self):
          self._server.close_server()
  
      def close_client(self):
          self._client.close_client()
  
      def client_send_packet_over_udp(self, packet): 
          self._client.send_packet_over_udp(packet)
  
      def server_receive_packet_over_udp(self):
          return self._server.receive_packet_over_udp()
  
      def server_send_packet_over_udp(self, packet): 
          self._server.send_packet_over_udp(packet)
  
      def client_receive_packet_over_udp(self):
          return self._client.receive_packet_over_udp()
  
subject: remove unnecessary lines