Add return annotation to catalog.registerFunction and fix style

Author: zero323

python/pyspark/sql/catalog.py

@@ -237,6 +237,7 @@ def registerFunction(self, name, f, returnType=StringType()):
         :param name: name of the UDF
         :param f: python function
         :param returnType: a :class:`pyspark.sql.types.DataType` object
+        :return a wrapped :class:`UserDefinedFunction`
 
         >>> strlen = spark.catalog.registerFunction("stringLengthString", len)
         >>> spark.sql("SELECT stringLengthString('test')").collect()

python/pyspark/sql/context.py

@@ -185,7 +185,7 @@ def registerFunction(self, name, f, returnType=StringType()):
         :param name: name of the UDF
         :param f: python function
         :param returnType: a :class:`pyspark.sql.types.DataType` object
-        :return a wrapped :class:`UserDefinedFunction` 
+        :return a wrapped :class:`UserDefinedFunction`
 
         >>> strlen = sqlContext.registerFunction("stringLengthString", lambda x: len(x))
         >>> sqlContext.sql("SELECT stringLengthString('test')").collect()

python/pyspark/sql/tests.py

@@ -624,7 +624,6 @@ def f(x):
         self.assertEqual(f, f_.func)
         self.assertEqual(return_type, f_.returnType)
 
-
     def test_basic_functions(self):
         rdd = self.sc.parallelize(['{"foo":"bar"}', '{"foo":"baz"}'])
         df = self.spark.read.json(rdd)