check plausibility of job/ machine numbers of JobShopProblem

contributes to #3

src/JobShopParser/__init__.py

@@ -1,5 +1,6 @@
 from typing import List, Tuple, Sequence, Optional, Union
 import arpeggio
+from itertools import chain
 
 __all__ = ["jobshop1_parser", "jobshop2_parser"]
 
@@ -42,6 +43,12 @@ class ParseError(Exception):
 class JobShopProblem:
 
     def __init__(self, jobs: int, machines: int, problem_data: List[List[Tuple[int, int]]], name: str = 'unnamed', description: str = '') -> None:
+        # check plausibility of input
+        if len(problem_data) != jobs:
+            raise ParseError("Given number of jobs for problem \"{}\" differs from actual job data.".format(name))
+        if max([machine for (duration, machine) in chain.from_iterable(problem_data)]) > machines-1:
+            raise ParseError("Higher machine number found in problem data than specified at problem head")
+
         self.description = description
         self.name = name
         self.problem_data = problem_data