input: Write a python function to generate the multiplication table for numbers from 1 to 9.
  assert generate_multiplication_table() == ['1 x 1 = 1', '1 x 2 = 2', '1 x 3 = 3', ..., '9 x 9 = 81']
output: def generate_multiplication_table():
      table = []
      for i in range(1, 10):
          for j in range(1, 10):
              table.append(f'{i} x {j} = {i * j}')
      return table