diff --git a/annotation/scripts/__pycache__/transcript_classes.cpython-36.pyc b/annotation/scripts/__pycache__/transcript_classes.cpython-36.pyc
new file mode 100644
index 0000000..4c66903
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diff --git a/annotation/scripts/__pycache__/transcript_classes.cpython-37.pyc b/annotation/scripts/__pycache__/transcript_classes.cpython-37.pyc
new file mode 100644
index 0000000..04b7158
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diff --git a/annotation/scripts/transcript_classes.py b/annotation/scripts/transcript_classes.py
index 60cf443..e06bbe4 100644
--- a/annotation/scripts/transcript_classes.py
+++ b/annotation/scripts/transcript_classes.py
@@ -335,6 +335,10 @@ def parse_spreadsheet(df, GFFs, CTGm):
                         for line in lines_split:
                             if line.strip():
                                 gff_split = line.split('\t')
+                                if len(gff_split) != 9:
+                                    print("erroneous line: ", file = sys.stderr)
+                                    print(gff_split, file = sys.stderr)
+                                    raise IOError("This line was too long.")
                                 #get the info if the gene is spliced in an intron
                                 SII=""
                                 if not pd.isnull(row["spliced_in_intron"]):