TheAlgorithms · poyea · Oct 21, 2021 · Oct 18, 2021 · Oct 18, 2021 · Oct 18, 2021
diff --git a/DIRECTORY.md b/DIRECTORY.md
@@ -513,9 +513,10 @@
   * [Runge Kutta](https://github.com/TheAlgorithms/Python/blob/master/maths/runge_kutta.py)
   * [Segmented Sieve](https://github.com/TheAlgorithms/Python/blob/master/maths/segmented_sieve.py)
   * Series
-    * [Arithmetic Mean](https://github.com/TheAlgorithms/Python/blob/master/maths/series/arithmetic_mean.py)
-    * [Geometric Mean](https://github.com/TheAlgorithms/Python/blob/master/maths/series/geometric_mean.py)
+    * [Arithmetic](https://github.com/TheAlgorithms/Python/blob/master/maths/series/arithmetic.py)
+    * [Geometric](https://github.com/TheAlgorithms/Python/blob/master/maths/series/geometric.py)
     * [Geometric Series](https://github.com/TheAlgorithms/Python/blob/master/maths/series/geometric_series.py)
+    * [Harmonic](https://github.com/TheAlgorithms/Python/blob/master/maths/series/harmonic.py)
     * [Harmonic Series](https://github.com/TheAlgorithms/Python/blob/master/maths/series/harmonic_series.py)
     * [P Series](https://github.com/TheAlgorithms/Python/blob/master/maths/series/p_series.py)
   * [Sieve Of Eratosthenes](https://github.com/TheAlgorithms/Python/blob/master/maths/sieve_of_eratosthenes.py)
@@ -933,6 +934,7 @@
   * [Indian Phone Validator](https://github.com/TheAlgorithms/Python/blob/master/strings/indian_phone_validator.py)
   * [Is Palindrome](https://github.com/TheAlgorithms/Python/blob/master/strings/is_palindrome.py)
   * [Jaro Winkler](https://github.com/TheAlgorithms/Python/blob/master/strings/jaro_winkler.py)
+  * [Join](https://github.com/TheAlgorithms/Python/blob/master/strings/join.py)
   * [Knuth Morris Pratt](https://github.com/TheAlgorithms/Python/blob/master/strings/knuth_morris_pratt.py)
   * [Levenshtein Distance](https://github.com/TheAlgorithms/Python/blob/master/strings/levenshtein_distance.py)
   * [Lower](https://github.com/TheAlgorithms/Python/blob/master/strings/lower.py)
@@ -967,6 +969,7 @@
   * [Fetch Jobs](https://github.com/TheAlgorithms/Python/blob/master/web_programming/fetch_jobs.py)
   * [Get Imdb Top 250 Movies Csv](https://github.com/TheAlgorithms/Python/blob/master/web_programming/get_imdb_top_250_movies_csv.py)
   * [Get Imdbtop](https://github.com/TheAlgorithms/Python/blob/master/web_programming/get_imdbtop.py)
+  * [Giphy](https://github.com/TheAlgorithms/Python/blob/master/web_programming/giphy.py)
   * [Instagram Crawler](https://github.com/TheAlgorithms/Python/blob/master/web_programming/instagram_crawler.py)
   * [Instagram Pic](https://github.com/TheAlgorithms/Python/blob/master/web_programming/instagram_pic.py)
   * [Instagram Video](https://github.com/TheAlgorithms/Python/blob/master/web_programming/instagram_video.py)

diff --git a/maths/check_polygon.py b/maths/check_polygon.py
@@ -1,7 +1,7 @@
-from typing import List
+from __future__ import annotations
 
 
-def check_polygon(nums: List) -> bool:
+def check_polygon(nums: list[float]) -> bool:
     """
     Takes list of possible side lengths and determines whether a
     two-dimensional polygon with such side lengths can exist.
@@ -14,15 +14,28 @@ def check_polygon(nums: List) -> bool:
     True
     >>> check_polygon([3, 7, 13, 2])
     False
+    >>> check_polygon([1, 4.3, 5.2, 12.2])
+    False
+    >>> nums = [3, 7, 13, 2]
+    >>> _ = check_polygon(nums) #   Run function, do not show answer in output
+    >>> nums #  Check numbers are not reordered
+    [3, 7, 13, 2]
     >>> check_polygon([])
     Traceback (most recent call last):
         ...
-    ValueError: List is invalid
+    ValueError: Monogons and Digons are not polygons in the Euclidean space
+    >>> check_polygon([-2, 5, 6])
+    Traceback (most recent call last):
+        ...
+    ValueError: All values must be greater than 0
     """
-    if not nums:
-        raise ValueError("List is invalid")
-    nums.sort()
-    return nums.pop() < sum(nums)
+    if len(nums) < 2:
+        raise ValueError("Monogons and Digons are not polygons in the Euclidean space")
+    if any(i <= 0 for i in nums):
+        raise ValueError("All values must be greater than 0")
+    copy_nums = nums.copy()
+    copy_nums.sort()
+    return copy_nums[-1] < sum(copy_nums[:-1])
 
 
 if __name__ == "__main__":