Error when pushing to heroku: App not compatible with buildpack

[Mathias Durrer]

Hi,

because heroku has disabled the github integration, i am currently pushing my code through the heroku CLI. I am getting this error: 

        -----> Using buildpack: heroku/python

remote: -----> App not compatible with buildpack: https://buildpackregistry.s3.amazonaws.com/buildpacks/heroku/python.tgz
remote:        More info: https://devcenter.heroku.com/articles/buildpacks#detection-failure
remote:
remote:  !     Push failed

In my requirements.txt file and in the runtime.txt i have specified the python version as follws: python-3.7.13

Can anybody help how to debug this error?

Best,

Mathias