text: # Create a calculator function
  # The function should accept three parameters:
  # first_number: a numeric value for the math operation
  # second_number: a numeric value for the math operation
  # operation: the word 'add' or 'subtract'. The default operation is 'add'
  # the function should return the result of the two numbers added or subtracted
  # based on the value passed in for the operator
  def calculator(first_number, second_number, operation='ADD'):
      if operation.upper() == 'ADD':
          return(float(first_number) + float(second_number))
      elif operation.upper() =='SUBTRACT':
          return(float(first_number) - float(second_number))
      else:
          return('Invalid operation please specify ADD or SUBTRACT')
  
  
  # Test your function using named notation passing in only the numbers 6 and 4
  # Should return 10
  print('Adding 6 + 4 = ' + str(calculator(first_number=6, second_number=4)))
  
  # Test your function using named notation with the values 6, 4, and subtract 
  # Should return 2
  print('Subtracting 6 - 4 = ' + str(calculator(first_number=6, second_number=4, operation='subtract')))
  
  # BONUS: Test your function with the values 6, 4 and divide 
  # Have your function return an error message when invalid values are received
  print('Dividing 6 / 4 = ' + str(calculator(first_number=6, second_number=4, operation='divide')))
  