Delete a node in BST

class Solution:
    def deleteNode(self, root: Optional[TreeNode], key: int) -> Optional[TreeNode]:
        def getMin(x):
            while x.left:
                x=x.left
            return x.val

        def delete(root,key):
            if not root:return None
            if root.val<key:
                root.right=delete(root.right,key)
            elif root.val>key:
                root.left=delete(root.left,key)
            else:
                #if it lead
                if not root.left and not root.right:
                    root=None
                #if it has one child
                elif not root.left:
                    root=root.right
                elif not root.right:
                    root=root.left
                #if it has two children
                else:
                    swap=getMin(root.right)
                    root.val=swap
                    root.right=delete(root.right,swap)
            return root
        return delete(root,key)