python list comprehension for loop

Let's make a 'python list & dictionary comprehension for loop' example. It selects equal or greater than average value, then returns max 50 elements from dictionary.

def pick_biggest_elements(my_dict):
    values = [x for x in my_dict.values()]
    values.sort()
    average = sum(values) / float(len(values))
    upper_side = [el for el in values if el >= average]
    temp = [key for key, value in my_dict.items() if value in upper_side]
    if len(temp) > 50:
        temp = temp[-50:]
    return [eval(a) for a in temp]