incrementhelper in kerashelper is incorrect

[mattiasakesson]

Severity

• Critical/Blocker (select if the issue makes the application unusable or causes serious data loss)
• [ x] High (select if the issue affects a major feature and there is no workaround or the available workaround is very complex)
• Medium (select if the issue affects a minor feature or affects a major feature but has an easy enough workaround to not cause any major inconvenience)
• Low (select if the issue doesn't significantly affect the user experience, like minor visual bugs)

Describe the bug
A clear and concise description of what the bug is.
The bug calculate the weights contribution incorrectly

Environment:

• OS: [e.g. mac OS]
• Version: [e.g. macOS Catalina]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Reproduction Steps
Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error
   create 2 client, one with metadata num_examples=0 and the other one with a positive integer, the global model update will then be the one with num_examples=0.

Expected behavior
A clear and concise description of what you expected to happen.
Incorrect model contribution

Screenshots
If applicable, add screenshots to help explain your problem.

Contact Details
An e-mail address in case we need to contact you for further details regarding this issue.