Adding docttest to to_zero_count()

src/resources/utilities.py

@@ -22,12 +22,18 @@ def to_zero_count(page_no):
     Will subtract 1 from the argument it gets, converting it to an int.
     If the conversion fails or the argument it's negatives it returns zero instead.
     
+    >>> to_zero_count(3)
+    2
+    >>> to_zero_count('a')
+    0
+
     Args:
         page_no: An integer
 
     Returns:
         It returns page_no - 1 if page_no can be safely converted to an integer else it returns zero.
         If page_no is negative, it returns zero.
+
     """
     try:
         page_no = int(page_no) - 1