Removing text field border after applying it

I encountered this problem today

I wanted to show to the user that a particular text field could be edited. Hence, I added a borderStyle with

self.phoneCodeTextField.borderStyle = .Line

But the problem is, I cannot remove the borderStyle with 

self.phoneCodeTextField.borderStyle = .None

Solution:

Make the textfield border rounded rect first before removing the border

self.phoneCodeTextField.borderStyle = .RoundedRect

self.phoneCodeTextField.borderStyle = .None