Made a change to directly iterate 'RSTAGS' instead of calling '.keys()' in the...

Made a change to directly iterate 'RSTAGS' instead of calling '.keys()' in the 'check_sampling' function in 'input_checks.py'.

toarstats/input_checks.py

@@ -29,7 +29,7 @@ def check_sampling(sampling_in):
     if not isinstance(sampling_in, str):
         return None
     sampling_out = sampling_in.strip()
-    if sampling_out not in RSTAGS.keys() | {"vegseason"}:
+    if sampling_out not in RSTAGS | {"vegseason"}:
         return None
     return sampling_out