Apply suggestions from code review

Co-Authored-By: Mathias Goncalves <[email protected]>

Author: oesteban

nitransforms/io/fsl.py

@@ -103,7 +103,14 @@ def from_string(cls, string):
 
     @classmethod
     def from_filename(cls, filename):
-        """Read the struct from a file given its path."""
+        """
+        Read the struct from a file given its path.
+
+        If the file does not exist, then indexed names
+        with the zero-padded suffix ``.NNN`` are
+        attempted, following FSL's MCFLIRT conventions.
+
+        """
         if os.path.exists(str(filename)):
             return super().from_filename(filename)
 

nitransforms/io/itk.py

@@ -212,7 +212,15 @@ def from_fileobj(cls, fileobj, check=True):
 
     @classmethod
     def from_ras(cls, ras, moving=None, reference=None):
-        """Create an ITK affine from a nitransform's RAS+ matrix."""
+        """
+        Create an ITK affine from a nitransform's RAS+ matrix.
+
+        The moving and reference parameters are included in this
+        method's signature for a consistent API, but they have no
+        effect on this particular method because ITK already uses
+        RAS+ coordinates to describe transfroms internally.
+
+        """
         _self = cls()
         _self.xforms = [cls._inner_type.from_ras(ras[i, ...], index=i)
                         for i in range(ras.shape[0])]
@@ -225,8 +233,11 @@ def from_string(cls, string):
         lines = [l.strip() for l in string.splitlines()
                  if l.strip()]
 
-        if not lines or not lines[0].startswith('#') or \
-           'Insight Transform File V1.0' not in lines[0]:
+        if (
+            not lines or
+            not lines[0].startswith('#') or
+           'Insight Transform File V1.0' not in lines[0]
+           ):
             raise TransformFileError('Unknown Insight Transform File format.')
 
         string = '\n'.join(lines[1:])

nitransforms/io/lta.py

@@ -177,9 +177,9 @@ def to_string(self):
             ('{:18.15e} ' * 4).format(*sa['m_L'][2]),
             ('{:18.15e} ' * 4).format(*sa['m_L'][3]),
             'src volume info',
-            '%s' % self['src'],
+            str(self['src']),
             'dst volume info',
-            '%s' % self['dst'],
+            str(self['dst']),
         ]
         return '\n'.join(lines)