Add doctest for select_first.
@@ -218,6 +218,12 @@ def select_first(in_files):
Used to grab the first echo's file when processing
multi-echo data through workflows that only accept
a single file.
+
+ >>> select_first('some/file.nii.gz')
+ 'some/file.nii.gz'
+ >>> select_first(['some/file1.nii.gz', 'some/file2.nii.gz'])
+ 'some/file1.nii.gz'
+
"""
if isinstance(in_files, list):
return in_files[0]
