input: Write a function to suggest a valid Python syntax to calculate the sum of two variables using lambda. 
  assert calculate_sum(a=3, b=4)=='sum = lambda a, b : a + b\nprint(sum(3,4))'
  assert calculate_sum(a=1, b=1)=='sum = lambda a, b : a + b\nprint(sum(1,1))'
  assert calculate_sum(a=-5, b=5)=='sum = lambda a, b : a + b\nprint(sum(-5,5))'
  assert calculate_sum(a=0, b=0)=='sum = lambda a, b : a + b\nprint(sum(0,0))'
  assert calculate_sum(a=-1, b=1)=='sum = lambda a, b : a + b\nprint(sum(-1,1))'
output: def calculate_sum(a, b):
      return f'sum = lambda a, b : a + b\nprint(sum({a},{b}))'