keyword and sentiment analysis map reduce mapper combiner and reducer program

Question

task is to  analyse a range of Amazon reviews and look for the most common word associated with a particular keyword and sentiment. You are provided with a file containing keywords to search for and a list of 10,000 reviews to search through. Each review is on a single line and comprises of a title, a review and a sentiment rating where 1 is a negative sentiment and 2 is a positive sentiment. The data are contained in a file called reviews.txt, . Your task is to write a Python based Hadoop Map/Reduce solution that will, in a single run, find all reviews that contain the set of target key words and find the most common word that occurs for that keyword and associated sentiment across all reviews. The key words are provided in a file called keywords.txt