MATLAB: Configure Matlab to use Python without pyenv

apipypyenvpythonspyder

I am trying to call Python from Matlab R2019a on a Windows 10 PC. I have Python 3.7 installed under Spyder 3, but Matlab cannot see it.
>> pyversion
       version: ''
    executable: ''
       library: ''
          home: ''
      isloaded: 0
Because R2019a predates the pyenv() command, I am unable to follow the instructions here and here to resolve the problem. How can Matlab be configured to use Python without access to pyenv?
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