input: 
  def find_customer(customers: dict, name: str) -> str:
      """ Given a dictionary of customers with their names as keys and their data as values,
      find and return the data of the specified customer. If the customer is not found,
      return "Customer not found."
      
      >>> find_customer({'John Doe': '123 Main St.', 'Jane Smith': '456 Elm St.'}, 'John Doe')
      '123 Main St.'
      >>> find_customer({'John Doe': '123 Main St.', 'Jane Smith': '456 Elm St.'}, 'Alice Johnson')
      'Customer not found.'
      """
      return customers.get(name, "Customer not found.")
  
  def main(customers: dict):
      """ Main function to run the command-line customer search application.
      Reads the customer name from command-line arguments and prints the result.
      
      >>> main({'John Doe': '123 Main St.', 'Jane Smith': '456 Elm St.'})
      Invalid arguments, please specify a customer name.
      """
      if len(sys.argv) == 2:
          name = sys.argv[1]
          print(find_customer(customers, name))
      else:
          print("Invalid arguments, please specify a customer name.")
  
output:     
  import sys
  
  def main(customers: dict):
      if len(sys.argv) == 2:
          name = sys.argv[1]
          print(find_customer(customers, name))
      else:
          print("Invalid arguments, please specify a customer name.")
  