title: Converting rdd to dataframe: AttributeError: 'RDD' object has no attribute 'toDF'
body: <pre><code>from pyspark import SparkContext, SparkConf
  from pyspark.sql import SQLContext
  
  conf = SparkConf().setAppName("myApp").setMaster("local")
  sc = SparkContext(conf=conf)
  
  a = sc.parallelize([[1, "a"], [2, "b"], [3, "c"], [4, "d"], [5, "e"]]).toDF(['ind', "state"])
  
  a.show()
  </code></pre>
  
  <p>Results in:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/Users/ktemlyakov/messing_around/SparkStuff/mock_maersk_data.py", line 7, in &lt;module&gt;
      a = sc.parallelize([[1, "a"], [2, "b"], [3, "c"], [4, "d"], [5, "e"]]).toDF(['ind', "state"])
  AttributeError: 'RDD' object has no attribute 'toDF'
  </code></pre>
  
  <p>What am I missing?</p>