can't access sys.stdin.read function

```sh
$ pip install -U web-pdb
$ cat a.py
import web_pdb; web_pdb.set_trace(port=5678)
$ python a.py

# Open browser in http://127.0.0.1:5678
(Pdb) import sys; sys.stdin.read
<bound method WebConsole.readline of <web_pdb.web_console.WebConsole object at 0x00000123C7ACA490>>
(Pdb) sys.stdin.read(1)
*** TypeError: readline() takes 1 positional argument but 2 were given
```