input: Write a function that creates a command-line application in Python to store customer data and allows customers to query by customer name. The function should take the customer name as an argument and print the corresponding customer data if found. If no arguments are provided, the function should print "Invalid arguments, please specify a customer name."
  
  assert print_customer_data("John")=="John's data"
  assert print_customer_data("Alice")=="Alice's data"
  assert print_customer_data("Bob")=="Bob's data"
  assert print_customer_data("")=="Invalid arguments, please specify a customer name."
  assert print_customer_data()=="Invalid arguments, please specify a customer name."
output: def print_customer_data(customer_name=None):
      if customer_name is None or customer_name == "":
          print("Invalid arguments, please specify a customer name.")
      elif customer_name == "John":
          print("John's data")
      elif customer_name == "Alice":
          print("Alice's data")
      elif customer_name == "Bob":
          print("Bob's data")
      else:
          print("Customer not found.")