Suppose that x1, . . . , xn form a random sample from the Bernoulli distribution with parameter , which is unknown, but it is

Suppose that x1, . . . , xn form a random sample from the Bernoulli distribution with parameter θ, which is unknown, but it is known that θ lies in the open interval 0 < θ <1. Show that the M.L.E. of θ does not exist if every observed value is 0 or if every observed value is 1.