in src/dataframe.rs [333:341]
fn with_columns(&self, exprs: Vec<PyExpr>) -> PyDataFusionResult<Self> {
let mut df = self.df.as_ref().clone();
for expr in exprs {
let expr: Expr = expr.into();
let name = format!("{}", expr.schema_name());
df = df.with_column(name.as_str(), expr)?
}
Ok(Self::new(df))
}