Attempt to fix issue with new pandas where Index no longer inherits from ndarray

Author: njsmith

patsy/design_info.py

@@ -277,7 +277,7 @@ def from_array(cls, array_like, default_column_prefix="column"):
         if arr.ndim > 2:
             raise ValueError("design matrix can't have >2 dimensions")
         columns = getattr(arr, "columns", range(arr.shape[1]))
-        if (isinstance(columns, np.ndarray)
+        if (hasattr(columns, "dtype")
             and not np.issubdtype(columns.dtype, np.integer)):
             column_names = [str(obj) for obj in columns]
         else: