input: Write a function to make the given Python code snippet more efficient by reducing the number of conditional checks. The function should determine the commission rate based on the gross sales amount. If the gross sales are greater than or equal to 10000, the commission rate is 0.1. If the gross sales are greater than or equal to 5000 but less than 10000, the commission rate is 0.07. Otherwise, the commission rate is 0.05.
  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(3000)==0.05
  assert determine_commission_rate(10000)==0.1
  assert determine_commission_rate(5000)==0.07
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