如何在pyspark中读取具有不同模式的多个csv文件？

from pyspark.sql import SparkSession
from pyspark.sql.types import StructType

spark = SparkSession.builder.getOrCreate()

schema1 = StructType().add("col1", "string").add("col2", "integer")
schema2 = StructType().add("col3", "string").add("col4", "double")

df1 = spark.read.csv("file1.csv", header=True, schema=schema1)
df2 = spark.read.csv("file2.csv", header=True, schema=schema2)

df1.show()
df2.show()

merged_df = df1.union(df2)