pr #209

functional tests passed.
pylint wanted changes
```
% python repo_utils/pylint_maker.py
************* Module truvari.utils
truvari/utils.py:448:0: C0305: Trailing newlines (trailing-newlines)
truvari/utils.py:447:11: R1729: Use a generator instead 'any(os.path.exists(vcf_path + '.' + x) for x in vcf_index_ext)' (use-a-generator)
```

Updated `truvari/annotations/trf.py` to use the new method.

Added the new method to api docs in `docs/api/truvari.rst`

docs/api/truvari.rst

@@ -92,6 +92,10 @@ calc_hwe
 ^^^^^^^^
 .. autofunction:: calc_hwe
 
+check_vcf_index
+^^^^^^^^^^^^^^^
+.. autofunction:: check_vcf_index
+
 compress_index_vcf
 ^^^^^^^^^^^^^^^^^^
 .. autofunction:: compress_index_vcf

truvari/annotations/trf.py

@@ -633,7 +633,7 @@ def check_params(args):
     if not args.input.endswith((".vcf.gz", ".bcf.gz")):
         logging.error(f"{args.input} isn't compressed vcf")
         check_fail = True
-    if not os.path.exists(args.input + ".tbi") and not os.path.exists(args.input + ".csi"):
+    if not truvari.check_vcf_index(args.input):
         logging.error(f"{args.input}[.tbi|.csi] doesn't exit")
         check_fail = True
     if not args.repeats.endswith(".bed.gz"):

truvari/utils.py

@@ -444,5 +444,4 @@ def check_vcf_index(vcf_path):
     Return true if an index file is found for the vcf
     """
     vcf_index_ext = ['tbi','csi']
-    return any([os.path.exists(vcf_path + '.' + x) for x in vcf_index_ext])
-
+    return any(os.path.exists(vcf_path + '.' + x) for x in vcf_index_ext)