Best practices for importing rarely used package in Python

My Python package depends on an external library for a few of it's functions. This is a non-Python package and can be difficult to install, so I'd like users to still be able to use my package but have it fail when using any functions that depend on this non-Python package.

What is the standard practice for this? I could only import the non-Python package inside the methods that use it, but I really hate doing this

My current setup:

myInterface.py
myPackage/
--classA.py
--classB.py

The interfaces script myInterface.py imports classA and classB and classB imports the non-Python package. If the import fails I print a warning. If myMethod is called and the package isn't installed there will be some error downstream but I do not catch it anywhere, nor do I warn the user.

classB is imported every time the interface script is called so I can't have anything fail there, which is why I included the pass. Like I said above, I could import inside the method and have it fail there, but I really like keeping all of my imports in one place.

From classB.py

try:
    import someWeirdPackage
except ImportError:
    print("Cannot import someWeirdPackage")
    pass

class ClassB():
    ...
    def myMethod():
        swp = someWeirdPackage()
        ...