我正在与一个使用python 2.7的小组进行研究，必须卸载anaconda 3并将其替换为anaconda2。我需要为数据分析程序安装pyfits，所以我使用conda install -c cefca pyfits并感到不满意错误。我需要重新下载anaconda或其他内容吗？这是完整的错误：
WARNING conda.base.context:use_only_tar_bz2(632): Conda is constrained to only using the old .tar.bz2 file format because you have conda-build installed, and it is <3.18.3. Update or remove conda-build to get smaller downloads and faster extractions.
Collecting package metadata (repodata.json): done
Solving environment: |failed
UnsatisfiableError: The following specifications were found to be incompatible with each other:
- anaconda==2019.03=py27_0 -> mkl-service==1.1.2=py27hfbe908c_5
- anaconda==2019.03=py27_0 -> path.py==11.5.0=py27_0 -> importlib_metadata[version='>=0.5']
- anaconda==2019.03=py27_0 -> zipp==0.3.3=py27_1
- pkgs/main/osx-64::importlib_metadata==0.8=py27_0 -> zipp[version='>=0.3.2']
- pkgs/main/osx-64::mkl-service==1.1.2=py27hfbe908c_5
- pkgs/main/osx-64::path.py==11.5.0=py27_0 -> importlib_metadata[version='>=0.5']
- pkgs/main/osx-64::zipp==0.3.3=py27_1