input: from typing import List
  
  def determine_commission_rate(gross_sales: List[float]) -> List[float]:
      """ Determine the commission rate for each gross sales amount in the list.
      The commission rate is determined as follows:
      - If gross_sales >= 10000, the commission rate is 0.1
      - If gross_sales >= 5000 and gross_sales < 10000, the commission rate is 0.07
      - If gross_sales < 5000, the commission rate is 0.05
      
      >>> determine_commission_rate([12000, 7500, 4900])
      [0.1, 0.07, 0.05]
      >>> determine_commission_rate([15000, 9900, 5000, 4500])
      [0.1, 0.1, 0.07, 0.05]
      """
output:     commission_rates = []
      for sale in gross_sales:
          if sale >= 10000:
              commission_rates.append(0.1)
          elif sale >= 5000:
              commission_rates.append(0.07)
          else:
              commission_rates.append(0.05)
      return commission_rates