Error pip installing fbprophet, pystan installed fine, I tried different versions. My python is 3.6.7, tried all the answers suggested before

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I have attached a snapshot of the error msg. I am using python 3.6.7. I tried 3.7 and 3.8. pystan install successfully. I tried different versions of pystan as others suggested. I have been trying for a few days, googled all the answers and tried most to no avail. Others suggested using Anaconda, but I am trying to use pip install. Does fbprophet require a specific version of python?