BF: Correctly use data type's inherent range if the valid_range attribute is missing.

Author: Robert D. Vincent

nibabel/minc1.py

@@ -134,7 +134,7 @@ def _get_valid_range(self):
             try:
                 valid_range = [self._image.valid_min,
                                self._image.valid_max]
-            except AttributeError:
+            except (AttributeError, KeyError):
                 valid_range = [info.min, info.max]
         if valid_range[0] < info.min or valid_range[1] > info.max:
             raise ValueError('Valid range outside input '

nibabel/minc2.py

@@ -95,7 +95,7 @@ def _get_valid_range(self):
         info = np.iinfo(ddt.type)
         try:
             valid_range = self._image.attrs['valid_range']
-        except AttributeError:
+        except (AttributeError, KeyError):
             valid_range = [info.min, info.max]
         else:
             if valid_range[0] < info.min or valid_range[1] > info.max: