import collections


def extractWordFeatures(x):
    """
    Extract word features for a string x. Words are delimited by
    whitespace characters only.
    @param string x: 
    @return dict: feature vector representation of x.
    Example: "I am what I am" --> {'I': 2, 'am': 2, 'what': 1}
    """
    # BEGIN_YOUR_CODE (our solution is 4 lines of code, but don't worry if you deviate from this)
    wordDict=collections.defaultdict(float)
    for word in x.split():
        wordDict[word]+=1
    return wordDict
    # END_YOUR_CODE