diff --git a/src/JobShopParser/__init__.py b/src/JobShopParser/__init__.py
index 40615f6..b407706 100644
--- a/src/JobShopParser/__init__.py
+++ b/src/JobShopParser/__init__.py
@@ -1,6 +1,8 @@
 from typing import List, Tuple, Sequence, Optional, Union
 import arpeggio
 
+__all__ = ["jobshop1_parser", "jobshop2_parser"]
+
 grammar = """
         # starting point for jobshop1 input file
         job_shop1       = skip_preface
@@ -78,7 +80,7 @@ class JobShopVisitor(arpeggio.PTNodeVisitor):
         if len(job_numbers) % 2 ==1:
             raise ParseError("Odd number of numbers in job data")
         # returns list of (duration, machine) tuples
-        return list(zip(job_numbers[1::2], job_numbers[0::2]))
+                return list(zip(job_numbers[1::2], job_numbers[0::2])) # [::2] returns only every second element of the list
 
     def visit_problem_data(self, node: arpeggio.ParseTreeNode, children: arpeggio.SemanticActionResults) -> JobShopProblem:
         if self.debug: