It is because the pandas version. Newer version of pandas deleted the attribute "append". So I recommend you to try two fixing ways:
try to downgrade the pandas version. That is: conda/mamba remove pandas, and then conda/mamba install -y pandas==1.2.0. This failed for me again with the same attribute error.
try to change the source code with new attribute pandas.concat. The error message must give you the information of where the error occur, for me it was "/work/share/acuwbf4fll/liucan/software/scFEA/src/scFEA.py", line 172", so vi /work/share/acuwbf4fll/liucan/software/scFEA/src/scFEA.py, and change the source code. That is,
when I use the test data Melissa_full.csv to run the code, the below error appear.
AttributeError: 'DataFrame' object has no attribute 'append'. Did you mean: '_append'?
how do i fixed it. thank you