No module named 'bcolz'

Hello! I am running a code containing some fastai code on a CentOS linux machine. I installed, with conda, fastai0.7, but when I try to run the code I am getting this error: No module named ‘bcolz’. I installed it and now I am getting this: ModuleNotFoundError: No module named ‘cv2’. I installed that, too and I am asked for more and more things to install. Is this normal? What should I do? Thank you!