calculate-tin script error with bed file from s. cerevisiae

calculate-tin.py is giving an error when we used it for a bed file generated with s. cerevisiae gtf file. Below is the error we get:

@ 2021-07-13 16:36:37: Get BAM file(s) ...
Total 1 BAM file(s):
	results/samples/RPL7_3/map_genome/RPL7_3.se.Aligned.sortedByCoord.out.bam
@ 2021-07-13 16:36:37: Processing results/samples/RPL7_3/map_genome/RPL7_3.se.Aligned.sortedByCoord.out.bam
multiprocessing.pool.RemoteTraceback: 
"""
Traceback (most recent call last):
  File "/home/tavymi75/zarp/config/my_run/.snakemake/conda/c6ae2829/lib/python3.9/multiprocessing/pool.py", line 125, in worker
    result = (True, func(*args, **kwds))
  File "/home/tavymi75/zarp/config/my_run/.snakemake/conda/c6ae2829/lib/python3.9/multiprocessing/pool.py", line 48, in mapstar
    return list(map(*args))
  File "/home/tavymi75/zarp/config/my_run/.snakemake/conda/c6ae2829/bin/calculate-tin.py", line 361, in gf
    coverage = genebody_coverage(
  File "/home/tavymi75/zarp/config/my_run/.snakemake/conda/c6ae2829/bin/calculate-tin.py", line 260, in genebody_coverage
    start = positions[0] - 1
IndexError: list index out of range
"""

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/tavymi75/zarp/config/my_run/.snakemake/conda/c6ae2829/bin/calculate-tin.py", line 561, in <module>
    main()
  File "/home/tavymi75/zarp/config/my_run/.snakemake/conda/c6ae2829/bin/calculate-tin.py", line 541, in main
    pool.map(gf, conditions)
  File "/home/tavymi75/zarp/config/my_run/.snakemake/conda/c6ae2829/lib/python3.9/multiprocessing/pool.py", line 364, in map
    return self._map_async(func, iterable, mapstar, chunksize).get()
  File "/home/tavymi75/zarp/config/my_run/.snakemake/conda/c6ae2829/lib/python3.9/multiprocessing/pool.py", line 771, in get
    raise self._value
IndexError: list index out of range