diff --git a/harvester/proxy.py b/harvester/proxy.py
index be52075..979a611 100644
--- a/harvester/proxy.py
+++ b/harvester/proxy.py
@@ -6,6 +6,22 @@ import requests
 
 
 def fetch_list(url):
+    """Fetches proxy list from the given URL.
+
+    The HTTP response text will be searched for `ip:port` and `username:password@ip:port`
+    patterns to accommodate different source list formats.
+
+    If an error occurs while fetching the list, it will be logged with WARNING
+    and an empty list will be returned.
+
+    Args:
+        url (str): The URL to fetch proxy list from.
+
+    Returns:
+        list: A list of proxy server addresses fetched from the URL.
+            If an error occurs while fetching the list, it will be logged
+            with WARNING and an empty list will be returned.
+    """
     try:
         response = requests.get(url)
         response.raise_for_status()
@@ -14,9 +30,9 @@ def fetch_list(url):
         return []
 
     proxy_regex = r"(?:\b(?:[\S]+:)?(?:[\S]+)?@\b)?(?:\d{1,3}\.){3}\d{1,3}:\d+"
-    proxies = re.findall(proxy_regex, response.text)
+    proxies = set(re.findall(proxy_regex, response.text))
     logging.info(f'Fetched {len(proxies)} proxies from {url}')
-    return proxies
+    return list(proxies)
 
 
 def fetch_all(urls, max_workers=8):