OptiType throwing error: Invalid constraint expression about optitype HOT 7 OPEN

[Wed Sep 11 21:54:59 2019]
rule optitype_hlatyping:
    input: analysis/optitype/R2-2-N/R2-2-N.sorted.chr6.end1.fastq, analysis/optitype/R2-2-N/R2-2-N.sorted.chr6.end2.fastq
    output: analysis/optitype/R2-2-N/R2-2-N_result.tsv, analysis/optitype/R2-2-N/R2-2-N_coverage_plot.pdf
    jobid: 4
    benchmark: benchmarks/optitype/R2-2-N/R2-2-N.optitype_hlatyping.txt
    wildcards: sample=R2-2-N

/home/taing/miniconda3/envs/optitype/share/optitype-1.3.2-3/hlatyper.py:239: FutureWarning: from_items is deprecated. Please use DataFrame.from_dict(dict(items), ...) instead. DataFrame.from_dict(OrderedDict(items)) may be used to preserve the key order.
  pos_df = pd.DataFrame.from_items(iter(hits.items())).T
Traceback (most recent call last):
  File "/home/taing/miniconda3/envs/optitype/bin/OptiTypePipeline.py", line 421, in <module>
    result = op.solve(args.enumerate)
  File "/home/taing/miniconda3/envs/optitype/share/optitype-1.3.2-3/model.py", line 188, in solve
    self.__instance.c.add(expr >= 1)
  File "/home/taing/miniconda3/envs/optitype/lib/python2.7/site-packages/pyomo/core/base/constraint.py", line 800, in add
    return Constraint.add(self, self._nconstraints, expr)
  File "/home/taing/miniconda3/envs/optitype/lib/python2.7/site-packages/pyomo/core/base/constraint.py", line 413, in add
    """ % ( expr, expr and "Feasible" or "Infeasible", expr, self.cname(True) ) )
ValueError: 
Invalid constraint expression.  The constraint expression resolved to a
trivial Boolean (False) instead of a Pyomo object.  Please modify your rule
to return Constraint.Infeasible instead of False.

Error thrown for Constraint "c"

[Wed Sep 11 21:55:11 2019]
Error in rule optitype_hlatyping:
    jobid: 4
    output: analysis/optitype/R2-2-N/R2-2-N_result.tsv, analysis/optitype/R2-2-N/R2-2-N_coverage_plot.pdf
    shell:
        source activate /home/taing/miniconda3/envs/optitype/; OptiTypePipeline.py -i analysis/optitype/R2-2-N/R2-2-N.sorted.chr6.end1.fastq analysis/optitype/R2-2-N/R2-2-N.sorted.chr6.end2.fastq --dna -v -o analysis/optitype/R2-2-N/ -p R2-2-N --config cidc_wes/static/optitype/config.ini

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Exiting because a job execution failed. Look above for error message
Complete log: /mnt/ssd/wes/.snakemake/log/2019-09-11T215459.181918.snakemake.log