class Underscore(object):
    def map(self, arr, callback):
        newArr = []
        for i in arr:
            newArr.append(callback(i))
        return newArr
        
    def reduce(self):
        # your code here
        pass
    def find(self):
        # your code here
        pass
    def filter(self, param1, param2):
        # your code
        pass
    def reject(self):
        # your code
        pass
