Update client.py

[github4bhavin]

had to change it since it was throwing error on 2.7

[shirou]

Thank you.
But my Python 2.7.8 on Mac OS X,

Python 2.7.8 (default, Oct 19 2014, 16:03:53) 
[GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.51)] on darwin
>>> "http://{}:{}/".format("a", "b")
'http://a:b/'

works. What patch level version are you using?

[github4bhavin]

its actually 2.6

Python 2.6.6 (r266:84292, Jan 22 2014, 09:42:36)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-4)] on linux2

[shirou]

I hadn't know {} is only in 2.7+. Thank you.
But, your field name based approach is a little bit complex. How about using just {0} like

addr = "http://{0}:{1}/".format(host, port)

https://docs.python.org/2.7/library/string.html#format-string-syntax
And could you remove your comment about compatiblity?

If you change your PR, I will merge. Thank you for your contribution!