Fix doc build for metaclassed Polynomials

docs/source/conf.py

@@ -28,6 +28,9 @@ MOCK_MODULES = ['numpy', 'numpy.polynomial', 'numpy.polynomial.polynomial',
                 'h5py', 'pandas', 'opencg']
 sys.modules.update((mod_name, MagicMock()) for mod_name in MOCK_MODULES)
 
+import numpy as np
+np.polynomial.Polynomial = MagicMock
+
 
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the

openmc/data/function.py

@@ -1,6 +1,7 @@
 from abc import ABCMeta, abstractmethod
 from collections import Iterable, Callable
 from numbers import Real, Integral
+from six import with_metaclass
 
 import numpy as np
 
@@ -10,14 +11,11 @@ INTERPOLATION_SCHEME = {1: 'histogram', 2: 'linear-linear', 3: 'linear-log',
                         4: 'log-linear', 5: 'log-log'}
 
 
-class Function1D(object):
+class Function1D(with_metaclass(ABCMeta, object)):
     """A function of one independent variable with HDF5 support."""
 
-    def __init__(self): pass
-
-    def __call__(self):
-        raise NotImplemented('Subclasses of Function1D should overwrite the '
-                             '__call__ and to_hdf5 methods')
+    @abstractmethod
+    def __call__(self): pass
 
     @abstractmethod
     def to_hdf5(self, group, name='xy'):
@@ -31,8 +29,7 @@ class Function1D(object):
             Name of the dataset to create
 
         """
-        raise NotImplemented('Subclasses of Function1D should overwrite the '
-                             '__call__ and to_hdf5 methods')
+        pass
 
     @classmethod
     def from_hdf5(cls, dataset):