Given two sorted linked lists, merge them such that resulting linked list is also sorted.

class sll(object):
    def __init__(self,val):
        self.value = val
        self.next = None

    def __repr__(self):
        return str(self.value)

def merge_sorted_lists(head1,head2):
    result = sll(0)
    current = result

    while head1 and head2:
        if head1.value < head2.value:
            current.next = head1
            head1 = head1.next
        elif head2.value < head1.value:
            current.next = head2
            head2 = head2.next
        else:
            current.next = head1
            head1 = head1.next
            current = current.next
            current.next = head2
            head2 = head2.next
        current = current.next
    while head1:
        current.next = head1
        head1 = head1.next
        current = current.next

    while head2:
        current.next = head2
        head2 = head2.next
        current = current.next

    return result.next