This library appears to depend on yfinance. Is there a reason that that dependency isn't specified in its setup.py?

Edit: That question has now been deleted. Here's a copy of what it said for posterity, with a few small edits for context:

I'm trying to push my app [to Heroku] that uses module: fix-yahoo-finance, however in order to install that module i need to install module called yfinance first.
So I placed yfinance module at top of requirements.txt list and the other one at the bottom. However when I push my app to heroku it still gives me an error:

remote:          Downloading https://files.pythonhosted.org/packages/a5/f3/aba3b563452faaea71b4161754991e3143751ec9141d83c4bce05992332a/fix-yahoo-finance-0.1.37.tar.gz
remote:            Complete output from command python setup.py egg_info:
remote:            Traceback (most recent call last):
remote:              File "<string>", line 1, in <module>
remote:              File "/tmp/pip-build-k3a2lnr1/fix-yahoo-finance/setup.py", line 19, in <module>
remote:                from fix_yahoo_finance import __version__
remote:              File "/tmp/pip-build-k3a2lnr1/fix-yahoo-finance/fix_yahoo_finance/__init__.py",
line 22, in <module>
remote:                import yfinance
remote:            ModuleNotFoundError: No module named 'yfinance'
remote:
remote:            ----------------------------------------
remote:        Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-k3a2lnr1/fix-yahoo-finance/

So I wonder what Im doing wrong. And how to fix this issue?