在PySpark 2.0中，如何计算不包括周末的日期范围内的累计和？

from pyspark.sql import SparkSession
from pyspark.sql.functions import col, date_format, expr, when
from pyspark.sql.window import Window

spark = SparkSession.builder.appName("Weekday Accumulative Sum").getOrCreate()

data = [("2022-01-01", 10), ("2022-01-02", 20), ("2022-01-03", 30), ("2022-01-04", 40), ("2022-01-05", 50), ("2022-01-06", 60), ("2022-01-07", 70)]
df = spark.createDataFrame(data, ["date", "value"])

df = df.withColumn("date", col("date").cast("date"))

df = df.withColumn("weekday", date_format(col("date"), "u").cast("integer"))

windowSpec = Window.orderBy("date").rowsBetween(Window.unboundedPreceding, Window.currentRow)

df = df.withColumn("value", when((col("weekday") == 6) | (col("weekday") == 7), 0).otherwise(col("value")))

df = df.withColumn("accumulative_sum", expr("sum(value) over (partition by weekday order by date)"))

df.show()