code style (add abstractmethod) (Gallopsled#2069)

Co-authored-by: Arusekk <[email protected]>

Author: zhouzq-thu

.gitignore

@@ -21,3 +21,4 @@ venv
 .idea
 __pycache__
 !.github
+.DS_Store

pwnlib/tubes/tube.py

@@ -2,6 +2,7 @@
 from __future__ import absolute_import
 from __future__ import division
 
+import abc
 import logging
 import re
 import six
@@ -1276,6 +1277,7 @@ def __exit__(self, type, value, traceback):
         self.close()
 
     # The minimal interface to be implemented by a child
+    @abc.abstractmethod
     def recv_raw(self, numb):
         """recv_raw(numb) -> str
 
@@ -1289,6 +1291,7 @@ def recv_raw(self, numb):
 
         raise EOFError('Not implemented')
 
+    @abc.abstractmethod
     def send_raw(self, data):
         """send_raw(data)