linked list creation and implementing operations

class Node:
    def __init__(self,data):
        self.data = data
        self.ref = None

class LinkedList:
    def __init__(self):
        self.head = None

    def print_LL(self):
        if self.head is None:
            print("Linked list is empty!")
        else:
            n = self.head
            while n is not None:
                print(n.data,"--->",end=" ")
                n = n.ref
    def add_begin(self,data):
      new_node = Node(data)
      new_node.ref = self.head
      self.head = new_node
    def add_end(self,data):
        new_node = Node(data)
        if self.head is None:
            self.head = new_node
        else:
            n = self.head
            while n.ref is not None:
                n = n.ref
            n.ref = new_node
    def add_after(self,data,x):
        n = self.head
        while n is not None:
            if x==n.data:
                break
            n = n.ref
        if n is None:
            print("node is not presesnt in LL")
        else:
            new_node = Node(data)
            new_node.ref = n.ref
            n.ref = new_node
    def add_before(self,data,x):
        if self.head is None:
            print("Linked List is empty!")
            return
        if self.head.data==x:
            new_node = Node(data)
            new_node.ref = self.head
            self.head = new_node
            return
        n = self.head
        while n.ref is not None:
            if n.ref.data==x:
                break
            n = n.ref        
        if n.ref is None:
            print("Node is not found!")
        else:
            new_node = Node(data)
            new_node.ref = n.ref
            n.ref = new_node
    def delete_begin(self):
        if self.head is None:
            print("Linked List is empty can't delete!")
        else:
            self.head=self.head.ref
    def delete_end(self):
       if self.head is None:
        print("ll is empty so we can't delete nodes")
       else:
        n=self.head
        while n.ref.ref is not None:
            n=n.ref
        n.ref=None
LL1=LinkedList()
LL1.print_LL()
print("\n")
LL1.add_begin(30)
LL1.print_LL()
print("\n")
LL1.add_end(10)
LL1.print_LL()
print("\n")
LL1.add_before(40,30)
LL1.print_LL()
print("\n")
LL1.add_after(20,30)
LL1.print_LL()
print("\n")
LL1.delete_begin()
LL1.print_LL()
print("\n")
LL1.delete_end()
LL1.print_LL()
print("\n")