input: Write a function to optimize the given Python code snippet for determining a commission rate based on gross sales. If the gross sales are greater than or equal to 10000, the commission rate should be 0.1. If the gross sales are between 5000 (inclusive) and 10000 (exclusive), the commission rate should be 0.07. If the gross sales are less than 5000, the commission rate should be 0.05. The function should return the commission rate directly in each condition.
  assert determine_commission_rate(12000)==0.1
  assert determine_commission_rate(7500)==0.07
  assert determine_commission_rate(4500)==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