How to resolve Python package depencencies with pipenv?

Question

I am using pipenv to handle a Python package dependencies.

The Python package is using two packages (named pckg1 and pckg2) that relies on

Answer 1

pipenv lock
Locking [dev-packages] dependencies…
Locking [packages] dependencies…

Warning: Your dependencies could not be resolved. You likely have a mismatch in your sub-dependencies.
  First try clearing your dependency cache with $ pipenv lock --clear, then try the original command again.
 Alternatively, you can use $ pipenv install --skip-lock to bypass this mechanism, then run $ pipenv graph to inspect the situation.
  Hint: try $ pipenv lock --pre if it is a pre-release dependency.

pipenv install --clean