MAINT: remove from_function. We can revisit this later

zipline/pipeline/factors/factor.py

@@ -541,48 +541,3 @@ class CustomFactor(RequiredWindowLengthMixin, CustomTermMixin, Factor):
         if self.dtype != float64:
             raise UnsupportedDataType(dtype=self.dtype)
         return super(CustomFactor, self)._validate()
-
-    @classmethod
-    def from_function(cls, f, window_length, *inputs):
-        """Construct a new factor type or factor from an arbitrary callable.
-
-        Parameters
-        ----------
-        f : callable
-            The callable to reduce the input data with.
-            This will be called with ``*input_data`` where each input data is
-            the lookback array for the input.
-        window_length : int
-            The size of the window of data. This is the length of each
-            input_data array.
-        *inputs : iterable of DataSet, optional
-            The inputs to the new factor. If this is not passed, then a new
-            factor type is created instead of a factor instance.
-
-        Returns
-        -------
-        factor : type or CustomFactor
-            A new custom factor class if not inputs are passed, otherwise
-            a new instance of a new custom factor class.
-        """
-        try:
-            name = f.__name__
-        except AttributeError:
-            name = '<function>'
-
-        def compute(self, today, assets, out, *data):
-            """Compute the values for the output by calling:
-            out[:] = {fn}(*data)
-            """
-            out[:] = f(*data)
-
-        compute.__doc__ = compute.__doc__.format(fn=name)
-
-        factor = type(name, (cls,), {
-            'compute': compute,
-            'window_length': window_length,
-        })
-
-        if inputs:
-            factor = factor(inputs)
-        return factor