multi-value-repeated-key-literal (F601)
Derived from the Pyflakes linter.
Fix is sometimes available.
What it does
Checks for dictionary literals that associate multiple values with the same key.
Why is this bad?
Dictionary keys should be unique. If a key is associated with multiple values, the earlier values will be overwritten. Including multiple values for the same key in a dictionary literal is likely a mistake.
Example
Use instead: