Question about data type for flag_masks
Question about the data type allowed for a flag_masks variable.

See CF.py code 

``` python
        type_ok = v.dtype in [np.character,
                                      np.dtype('b'),
                                      np.dtype('i4'),
                                      np.int32]
```

https://github.com/ioos/compliance-checker/blob/master/compliance_checker/cf/cf.py#L811

is there a reason why int8 and int32 are allowed and int16 is not. I previously had a file
with a flag_masks variable of "short' type not passing the CF checker

Thanks

@mhidas FYI

diff --git a/compliance_checker/cf/cf.py b/compliance_checker/cf/cf.py
index acc426f..885bd8f 100644
--- a/compliance_checker/cf/cf.py
+++ b/compliance_checker/cf/cf.py
@@ -854,11 +854,9 @@ class CFBaseCheck(BaseCheck):
                 ok_count = 0
 
                 same_type = flag_masks.dtype == v.dtype
-                type_ok = v.dtype in [np.character,
-                                      np.dtype('b'),
-                                      np.dtype('i4'),
-                                      np.int32]
-
+                type_ok = (np.issubdtype(v.dtype, int) or
+                           np.issubdtype(v.dtype, 'S') or
+                           np.issubdtype(v.dtype, 'b'))
                 if same_type:
                     ok_count += 1
                 else:
['compliance_checker/cf/cf.py']