input: Write a function to create a command-line application in Python that stores customer data and allows customers to query by customer name. The function should have a main function that processes command line arguments and calls a function to print customer data based on the provided customer name. If no customer name is provided, it should print an appropriate error message. If the given customer name is found, it should print the corresponding customer data.
  
  assert __name__ == "__main__"
  assert sys.argv[1] == "John"
  assert print_customer_data("John") == <prints customer data for John>
  assert sys.argv[1] == ""
  assert print("Invalid arguments, please specify a customer name.") == <prints error message>
  assert print_customer_data("Mary") == <prints customer data for Mary>
output: def print_customer_data(customer_name):
      customers = {
          "John": "Customer data for John",
          "Mary": "Customer data for Mary"
      }
      if customer_name in customers:
          print(customers[customer_name])
      else:
          print("Invalid arguments, please specify a customer name.")