No longer need proxy

zipline/pipeline/factors/factor.py

@@ -1,13 +1,11 @@
 """
 factor.py
 """
-from abc import ABCMeta
 from functools import wraps
 from operator import attrgetter
 from numbers import Number
 
 from numpy import inf, where
-from six import with_metaclass
 
 from zipline.errors import UnknownRankMethod
 from zipline.lib.normalize import naive_grouped_rowwise_apply
@@ -314,11 +312,8 @@ def mathfunc(self):
     )
 )
 
-FACTOR_DTYPES = frozenset([datetime64ns_dtype, float64_dtype, int64_dtype])
-
 
-class FactorProxy(with_metaclass(ABCMeta, object)):
-    pass
+FACTOR_DTYPES = frozenset([datetime64ns_dtype, float64_dtype, int64_dtype])
 
 
 class Factor(RestrictedDTypeMixin, ComputableTerm):
@@ -1047,8 +1042,6 @@ def isfinite(self):
         """
         return (-inf < self) & (self < inf)
 
-FactorProxy.register(Factor)
-
 
 class NumExprFactor(NumericalExpression, Factor):
     """