Merge pull request #4915 from chrishavlin/cf_radial_validation

add check for Sub_conventions for CFradial

yt/frontends/cf_radial/data_structures.py

@@ -310,11 +310,14 @@ def _is_valid(cls, filename: str, *args, **kwargs) -> bool:
  nc4_file = NetCDF4FileHandler(filename)
  with nc4_file.open_ds(keepweakref=True) as ds:
  con = "Conventions" # the attribute to check for file conventions
+ # note that the attributes here are potentially space- or
+ # comma-delimited strings, so we concatenate a single string
+ # to search for a substring.
  cons = "" # the value of the Conventions attribute
- for c in [con, con.lower()]:
+ for c in [con, con.lower(), "Sub_" + con.lower()]:
  if hasattr(ds, c):
  cons += getattr(ds, c)
- is_cfrad = "CF/Radial" in cons
+ is_cfrad = "CF/Radial" in cons or "CF-Radial" in cons
  except (OSError, AttributeError, ImportError):
  return False