I'm trying to package git-cola

it uses a makefile and such makefile calls the python machinery for
building (python setup.py ...) with some arguments

make cannot find the command "python"

starting phase `build'
make: python: Command not found
python setup.py build
make: python: Command not found
make: *** [Makefile:91: build] Error 127
phase `build' failed after 0.0 seconds

Python is in the inputs, though

Like this
(inputs
  `(("python" ,python)))

How can I let it find Python ?

Thanks