diff --git a/__pycache__/library.cpython-37.pyc b/__pycache__/library.cpython-37.pyc
index 2338485..e712bf9 100644
Binary files a/__pycache__/library.cpython-37.pyc and b/__pycache__/library.cpython-37.pyc differ
diff --git a/library.py b/library.py
index aec1504..84f84d2 100755
--- a/library.py
+++ b/library.py
@@ -2,12 +2,14 @@
 import json
 import os
 import re
+import zipfile
 from config import Config
 config = Config()
 
 
 class Catalogue:
     """Decodes and stores book information"""
+    """Step One: filter_books"""
     def __init__(self):
         self.file_list = []
         with open(config.book_shelf, 'r') as f:
@@ -26,7 +28,19 @@ class Catalogue:
                 self.file_list.append(self.scan_folder(_path))
             self.file_list.append(_path)
 
+    def scan_book(self, book):
+        _epub = zipfile.ZipFile(book)
+        with _epub as _epub_open:
+            try: _epub_open.open('content.opf'); return True
+            except Exception as e: print(e); return False
+
     def filter_books(self, ret=0):
+        """
+        filter_books(0) -> Catalogue.books
+        filter_books(1) -> self.books[]
+        :param ret: 0 -> create class property
+        :param ret: 1 -> create & return class property
+        """
         self.scan_folder()
         regx = re.compile(r"\.epub")
         self.books = list(filter(regx.search, filter(None, self.file_list)))
@@ -36,10 +50,17 @@ class Catalogue:
         else:
             return self.books
 
+    def filter_tags(self, book):
+        f_name = 'content.opf'
+        try:
+            content_opf = list(filter(re.search, book))
+        except:
+            return False
+
     def compare_shelf_current(self):
         try:
             self.books
         except Exception:
             self.filter_books()
         unique = set(self.books) - set(self.catalogue)
-        return unique
+        return unique
\ No newline at end of file
diff --git a/main.py b/main.py
index ab32539..19887e3 100755
--- a/main.py
+++ b/main.py
@@ -7,4 +7,5 @@ from library import Catalogue
 config = Config()
 
 InitFiles(config.file_array)
-
+Catalogue = Catalogue()
+book_list = Catalogue.filter_books(1)