如果一列是另一列的成员，如何过滤Spark dataframe

from pyspark.sql import SparkSession
from pyspark.sql.functions import col

spark = SparkSession.builder.getOrCreate()

data = [("John", "A"), ("Mike", "B"), ("Sarah", "A"), ("Emma", "C"), ("Tom", "B")]
df = spark.createDataFrame(data, ["Name", "Grade"])
df.show()

+-----+-----+
| Name|Grade|
+-----+-----+
| John|    A|
| Mike|    B|
|Sarah|    A|
| Emma|    C|
|  Tom|    B|
+-----+-----+

filtered_df = df.filter(col("Grade").isin(["A", "B"]))
filtered_df.show()

+-----+-----+
| Name|Grade|
+-----+-----+
| John|    A|
| Mike|    B|
|Sarah|    A|
|  Tom|    B|
+-----+-----+