input: Write a function to compute the sum of two given variables and store the result in a third variable. Then print the result. Given variables x and y, the function should return the sum as an integer.
  assert sum_of_variables(5, 8)==13
  assert sum_of_variables(10, 15)==25
  assert sum_of_variables(0, 0)==0
  assert sum_of_variables(-1, 1)==0
  assert sum_of_variables(-5, -3)==-8
output: def sum_of_variables(x, y):
      result = x + y
      return result