When I try to customize the classes of a transition component in a Material UI Accordion typescript complains about the missing classes property.

• The issue is present in the latest release.
• I have searched the issues of this repository and believe that this is not a duplicate.

Current Behavior 😯

Typescript complains when I try to customize the classes of a transition component in a Accordion.

Expected Behavior 🤔

Typescript shouldn't complain since customization of classes works.

Steps to Reproduce 🕹

https://codesandbox.io/s/sad-proskuriakova-j8432?file=/demo.tsx

Steps:

1. Add an Accordion
2. Try to customize the classes of the Transition component using TransitionProps={{ classes: { container: classes.transitionContainer } }}
3. Typescript definition does not contain a definition for classes.

Context 🔦

I am trying to customize the classes of a transition component in an Accordion.

Your Environment 🌎