input: Write a function to print the multiplication table of a given number from 1 to 10. The function should take an integer as input and print each multiplication in the format "{num} x {i} = {result}". If the input is invalid (e.g., not an integer), the function should print an error message.
  assert print_multiplication_table(5)==None
  assert print_multiplication_table(7)==None
output: def print_multiplication_table(num):
      if isinstance(num, int):
          for i in range(1, 11):
              print(f"{num} x {i} = {num * i}")
      else:
          print("Error: Input must be an integer.")