class_docstr: Eventloop interface.
class_docstr_tok: ["Eventloop","interface","."]
docstr: Start watching the file descriptor for read availability and then call
  the callback.
docstr_tok: ["Start","watching","the","file","descriptor","for","read","availability","and","then","call","the","callback","."]
code: def add_reader(self, fd, callback):
      """
      Start watching the file descriptor for read availability and then call
      the callback.
      """
  
file_path: catboost/contrib/python/prompt-toolkit/py2/prompt_toolkit/eventloop/base.py
imports: from __future__ import unicode_literals
  from abc import ABCMeta, abstractmethod
  from six import with_metaclass
label_desc: Use image node_id 5 for calling the EventLoop obj's underlying member method code with example usage: obj.add_reader(fd, callback) without return types