update loader and test to handle lines with brackets

tests/test_utils.py

diff --git a/tests/test_utils.py b/tests/test_utils.py
index e68f6a7..a9bb6a8 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -369,6 +369,7 @@
     vector_data = textwrap.dedent("""
 
         # http://tools.ietf.org/html/rfc1321
+        [irrelevant]
 
         Len = 0
         Msg = 00

tests/utils.py

diff --git a/tests/utils.py b/tests/utils.py
index cf25533..03b780f 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -127,7 +127,7 @@
     for line in vector_data:
         line = line.strip()
 
-        if not line or line.startswith("#"):
+        if not line or line.startswith("#") or line.startswith("["):
             continue
 
         if line.startswith("Len"):