input: Write a function to generate a random alphanumeric string of length 10.
  assert len(generate_alphanumeric_string()) == 10
  assert isinstance(generate_alphanumeric_string(), str)
  assert any(char.isdigit() for char in generate_alphanumeric_string())
  assert any(char.isalpha() for char in generate_alphanumeric_string())
output: import random
  import string
  
  def generate_alphanumeric_string():
      characters = string.ascii_letters + string.digits
      return ''.join(random.choice(characters) for _ in range(10))