input: Write a function to make the given Python code snippet more efficient by returning the commission rate directly within the if-elif-else structure. If gross_sales is greater than or equal to 10000, the function should return 0.1. If gross_sales is greater than or equal to 5000, the function should return 0.07. Otherwise, the function should return 0.05.
  assert determine_commission_rate(12000)==0.1
  assert determine_commission_rate(7500)==0.07
  assert determine_commission_rate(4000)==0.05
output: def determine_commission_rate(gross_sales):
      if gross_sales >= 10000:
          return 0.1
      elif gross_sales >= 5000:
          return 0.07
      else:
          return 0.05