mode.py

def mode(data):
    def loop(i, counts, c_max):
        max_val = c_max[0]
        if (i < 0):
            return max_val 
        else:
            c_val = data[i]
            new_count = counts.get(c_val, 0) + 1
            counts[c_val] = new_count
            max_dup = c_max[1]
            return loop(i - 1, counts, (c_val, new_count) if new_count > max_dup else c_max)
        
    return loop(len(data) - 1, dict(), (float('-inf'), 0))