input: Write a function to optimize the commission rate calculation by directly returning the commission rate instead of assigning it to a variable, and simplify the if-elif-else conditions. If the gross sales are greater than or equal to 10000, return 0.1. If gross sales are greater than or equal to 5000, return 0.07. Otherwise, return 0.05.
  
  
  assert determine_commission_rate(12000) == 0.1
  assert determine_circle_area(7500) == 0.07
  assert determine_circle_area(3000) == 0.05
  
output: def determine_commission_rate(gross_sales):
      return 0.1 if gross_sales >= 10000 else 0.07 if gross_sales >= 5000 else 0.05