pyspark
df = sc.parallelize([{'a': 1, 'b': 2, 'c': 3}, {'a': 8, 'b': 5, 'c': 6}, {
    'a': 3, 'b': 1, 'c': 0}]).toDF().cache()
df
df.columns

def column_add(a, b):
    pass
Add column sum as new column in PySpark dataframe