Fix ColumnNotFoundError

✅ Solution

ColumnNotFoundError in Ray often arises when a Ray Dataset operation refers to a column that doesn't exist in one of the underlying blocks, commonly after filtering or joining. Verify that the column name is spelled correctly and exists in *all* DataFrames/blocks participating in the operation; use `ds.schema()` or inspect individual blocks (e.g., `ds.take(1)`) to confirm its presence and case-sensitivity. If the column is missing, add it with a default value or handle the case where it might be absent before performing operations that require it.