Index: ammosreader/AbstractAmmosReader.py
===================================================================
--- ammosreader/AbstractAmmosReader.py	(revision d41827e93d71c7b765c429ecbf2336e2c07ef7d8)
+++ ammosreader/AbstractAmmosReader.py	(revision 809cb1603ded0de64dbfb27f1cee38fa8e392e8e)
@@ -29,16 +29,20 @@
     @property
     def file_name(self):
+        """I return the name of the original file."""
         return self.__file_name
 
     @property
     def ammos_file(self):
+        """I return the file to read the data from."""
         return self.__ammos_file
 
     @property
     def container(self):
+        """I return the container which stores the data read."""
         return self.__container
 
     @property
     def tags(self):
+        """I return all the tags."""
         return self.__tags
 
@@ -79,5 +83,4 @@
         :rtype: AmmosGlobalFrameHeader
         """
-
         header_size = AmmosGlobalFrameHeader.HEADER_SIZE
 
@@ -88,6 +91,9 @@
             return None
 
-        # FIXME: Catch exceptions and add some asserts
         current_global_frame_header = AmmosGlobalFrameHeader.from_bytes(bytes)
+
+        if current_global_frame_header is None:
+            return None
+
         logging.info("Current global frame header %s", current_global_frame_header)
         return current_global_frame_header
@@ -107,5 +113,6 @@
         global_frame_header = self.read_next_global_frame_header()
 
-        # print(global_frame_header)
+        if global_frame_header is None:
+            return None
 
         if global_frame_header is None: