Minimal viable product for interface specs as dicts

Author: mwaskom

nipype/interfaces/base.py

@@ -8,7 +8,7 @@
 
 Requires Packages to be installed
 """
-from __future__ import print_function, division, unicode_literals, absolute_import
+from __future__ import print_function, division, absolute_import
 from future import standard_library
 standard_library.install_aliases()
 from builtins import range, object, open, str, bytes
@@ -760,7 +760,6 @@ class BaseInterface(Interface):
     This class cannot be instantiated.
 
     """
-    input_spec = BaseInterfaceInputSpec
     _version = None
     _additional_metadata = []
     _redirect_x = False
@@ -771,6 +770,16 @@ def __init__(self, from_file=None, **inputs):
             raise Exception('No input_spec in class: %s' %
                             self.__class__.__name__)
 
+        if isinstance(self.input_spec, dict):
+            self.input_spec = type("AnonyomousInputSpec",
+                                   (BaseInterfaceInputSpec,),
+                                   self.input_spec)
+
+        if isinstance(self.output_spec, dict):
+            self.output_spec = type("AnonyomousOutputSpec",
+                                    (TraitedSpec,),
+                                    self.output_spec)
+
         self.inputs = self.input_spec(**inputs)
         self.estimated_memory_gb = 0.25
         self.num_threads = 1