DataFrame.transform - Spark Function Composition - Functions pre refactor

ExampleTransformLibPreRefactor.scala

def sumAmounts(df: DataFrame, by: Column*): DataFrame =
    df.groupBy(by: _*).agg(sum(col("amount")))

def extractPayerBeneficiary(columnName: String, df: DataFrame): DataFrame =
  df.withColumn(
      s"${columnName}_payer",
      regexp_extract(
        col(columnName),
        "paid by ([A-Z])",
        1
      )
    ).withColumn(
      s"${columnName}_beneficiary",
      regexp_extract(
        col(columnName),
        "to ([A-Z])",
        1
      )
    )