How to read from a csv file to create a scala Map object?

I have a path to a csv I'd like to read from. This csv includes three columns: "topic, key, value" I am using spark to read this file as a csv file. The file looks like the following(lookupFile.csv):

Topic,Key,Value
fruit,aaa,apple
fruit,bbb,orange
animal,ccc,cat
animal,ddd,dog

//I'm reading the file as follows
val lookup = SparkSession.read.option("delimeter", ",").option("header", "true").csv(lookupFile)

I'd like to take what I just read and return a map that has the following properties:

• The map uses the topic as a key
• The value of this map is a map of the "Key" and "Value" columns

My hope is that I would get a map that looks like the following:

val result = Map("fruit" -> Map("aaa" -> "apple", "bbb" -> "orange"),
                 "animal" -> Map("ccc" -> "cat", "ddd" -> "dog"))

Any ideas on how I can do this?