input: Write a function to generate a random password consisting of 8 characters. The password should include both letters and digits.
  assert generate_password()==some_output
  assert generate_password()==some_other_output
  assert generate_password()==another_output
  assert generate_password()==yet_another_output
  assert generate_password()==final_output
output: import random
  import string
  
  def generate_password():
      return ''.join(random.choices(string.ascii_letters + string.digits, k=8))