Coding style change for project_euler problem 36 and 35 (#3062)

* add problem url. Add typehint, default value and doctest

* run black

* add project url. add solution function for problem 35

* add space between imports on problem 35

* Update sol1.py

* Update sol1.py

Co-authored-by: Dhruv <dhruvmanila@gmail.com>

project_euler/problem_36/sol1.py

@@ -1,4 +1,9 @@
 """
+Project Euler Problem 36
+https://projecteuler.net/problem=36
+
+Problem Statement:
+
 Double-base palindromes
 Problem 36
 The decimal number, 585 = 10010010012 (binary), is palindromic in both bases.
@@ -10,17 +15,28 @@ base 10 and base 2.
 leading zeros.)
 """
 
+from typing import Union
 
-def is_palindrome(n):
+
+def is_palindrome(n: Union[int, str]) -> bool:
+    """
+    Return true if the input n is a palindrome.
+    Otherwise return false. n can be an integer or a string.
+
+    >>> is_palindrome(909)
+    True
+    >>> is_palindrome(908)
+    False
+    >>> is_palindrome('10101')
+    True
+    >>> is_palindrome('10111')
+    False
+    """
     n = str(n)
-
-    if n == n[::-1]:
-        return True
-    else:
-        return False
+    return True if n == n[::-1] else False
 
 
-def solution(n):
+def solution(n: int = 1000000):
     """Return the sum of all numbers, less than n , which are palindromic in
     base 10 and base 2.