fcompop is a library for function composition, the README demonstrates the following example:

>>> import fcompop
>>> # adding operators to builtin&user functions
>>> fcompop.inject()
>>> func = str._ >> (lambda x: x * 2 + 'abc') >> str.upper
>>> func(123)
'123123ABC'
>>> func = (lambda x: '-' + x)._ << chr << \
...        (lambda x: x + 1) << ord
>>> func('a')
'-b'

I really don’t know anything about functional programming, but some real world example would be better to understand, or at least to see. There must be a much better example, but the following is all I could come up with:

>>> adder = lambda addition: lambda x: x + addition
>>> multiplier = lambda multiplication: \
...              lambda x: x * multiplication
>>> f2c = float._ >> adder(-32) >> multiplier(5.0 / 9.0) >> \
...       "In Celsius, it's {} degree.".format
>>> f2c(212)
"In Celsius, it's 100.0 degree."

And yes, one lambda can achieve all these, that’s why I said there must be a better example for real and practical usage.

f2c = lambda f: "In Celsius, it's {} degree.".format(
                float(f) - 32 * 5 / 9)

fcompop is written by Jun Namikawa under the ISC License, currently version 0.3 (2014-05-14), for both Python 2 and 3.