in src/dataframe.rs [527:538]
fn union(&self, py_df: PyDataFrame, distinct: bool) -> PyDataFusionResult<Self> {
let new_df = if distinct {
self.df
.as_ref()
.clone()
.union_distinct(py_df.df.as_ref().clone())?
} else {
self.df.as_ref().clone().union(py_df.df.as_ref().clone())?
};
Ok(Self::new(new_df))
}