I found an interesting problem on https://www.codewars.com/kata/58de819eb76cf778fe00005c:
A palindrome is a word, phrase, number, or other sequence of characters which reads the same backward as forward. Examples of numerical palindromes are: 

2332
110011
54322345

For this kata, single digit numbers will not be considered numerical palindromes. 

For a given number ```num```, write a function to test if the number contains a numerical palindrome or not and return a boolean (true if it does and false if does not). Return "Not valid" if the input is not an integer or is less than 0. 

Note: Palindromes should be found without permutating ```num```. 

```
palindrome(5) => false
palindrome(1221) => true
palindrome(141221001) => true
palindrome(1215) => true 
palindrome(1294) => false 
palindrome("109982") => "Not valid"
```

I tried it in Python, but could not do it. Can you solve it?
import re

def palindrome(num):
    if not (isinstance(num, int) and num > 0):
        return 'Not valid'
    return bool(re.search(r'(.)\1|(.).\2', str(num)))