Change Python version

[guiaugustoga987]

I want to use the python module with python 2.7 but when I type cmake -- it finds python 3.6 :

-- The CXX compiler identification is GNU 7.5.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Found Python: /usr/bin/python3.6 (found version "3.6.9") found components: Interpreter Development NumPy Development.Module Development.Embed
-- Found Boost: /usr/include (found version "1.65.1") found components: python36 numpy36
-- Configuring done
-- Generating done
-- Build files have been written to: /home/gapc/kht/python/build

How do I set cmake to find python 2.7 ?