def min_max_median(lst):
    """ a function that takes a simple list of numbers lst as a parameter and returns a list with the min, max, and the median of lst. """
    s = sorted(lst)
    n = len(s)
    return [ s[0], s[-1], s[n//2] if n % 2 == 1  else (s[n//2 - 1] + s[n//2]) / 2]