fix: revise some imports from nipype, rework ImageMaths temporary patch

Author: oesteban

niworkflows/anat/ants.py

@@ -13,13 +13,12 @@
 from nipype.pipeline import engine as pe
 from nipype.interfaces import utility as niu
 from nipype.interfaces.ants import (
-    AI,
     Atropos,
     MultiplyImages,
     N4BiasFieldCorrection,
-    ResampleImageBySpacing,
     ThresholdImage,
 )
+from nipype.interfaces.ants.utils import AI, ResampleImageBySpacing
 
 from ..utils.misc import get_template_specs
 from ..utils.connections import pop_file as _pop

niworkflows/interfaces/ants.py

@@ -2,10 +2,17 @@
 # vi: set ft=python sts=4 ts=4 sw=4 et:
 """Patch ImageMath until https://github.com/nipy/nipype/pull/3210 is merged."""
 from nipype.interfaces.base import Str
-from nipype.interfaces.ants.utils import ImageMath as _ImageMath
+from nipype.interfaces.ants.utils import (
+    ImageMath as _ImageMath,
+    ImageMathInputSpec as _InputSpec
+)
 
 
-ImageMath = _ImageMath
-ImageMath.input_spec.operation = Str(
-    mandatory=True, position=3, argstr="%s", desc="operations and intputs"
-)
+class _ImageMathInputSpec(_InputSpec):
+    operation = Str(
+        mandatory=True, position=3, argstr="%s", desc="operations and intputs"
+    )
+
+
+class ImageMath(_ImageMath):
+    input_spec = _ImageMathInputSpec