input: Write a function to optimize the given Python code snippet that determines the commission rate based on the gross sales. The function should return the commission rate directly without storing it in a variable.
  
  def determine_commission_rate(gross_sales):
      if gross_sales >= 10000:
          return 0.1
      elif gross_sales >= 5000:
          return 0.07
      else:
          return 0.05
  
  assert determine_commission_rate(12000)==0.1
  assert determine_commission_rate(7500)==0.07
  assert determine_commission_rate(4500)==0.05
  assert determine_commission_rate(10000)==0.1
  assert determine_commission_rate(5000)==0.07
output: def determine_commission_rate(gross_sales):
      return 0.1 if gross_sales >= 10000 else 0.07 if gross_sales >= 5000 else 0.05