corrected docstring and improved readability

Author: TheChymera

nipype/interfaces/fsl/model.py

@@ -37,13 +37,15 @@ class Level1DesignInputSpec(BaseInterfaceInputSpec):
                               desc=('Session specific information generated '
                                     'by ``modelgen.SpecifyModel``'))
     bases = traits.Either(
-        traits.Dict(traits.Enum(
-            'dgamma'), traits.Dict(traits.Enum('derivs'), traits.Bool)),
+        traits.Dict(traits.Enum('dgamma'), traits.Dict(
+            traits.Enum('derivs'), traits.Bool)),
         traits.Dict(traits.Enum('gamma'), traits.Dict(
-                    traits.Enum('derivs', 'gammasigma', 'gammadelay'))),
-        traits.Dict(traits.Enum('custom'), traits.Dict(traits.Dict(traits.Enum('bfcustompath'), traits.Str))),
+            traits.Enum('derivs', 'gammasigma', 'gammadelay'))),
+        traits.Dict(traits.Enum('custom'), traits.Dict(
+            traits.Enum('bfcustompath'), traits.Str)),
         traits.Dict(traits.Enum('none'), traits.Dict()),
         traits.Dict(traits.Enum('none'), traits.Enum(None)),
+        ),
         mandatory=True,
         desc=("name of basis function and options e.g., "
               "{'dgamma': {'derivs': True}}"))