Ensures the output to be a character filename (or vector)
from an input image or nifti to have .mnc extension and
be converted to MNC when necessary
checkmnc(file, ...)# S4 method for nifti
checkmnc(file, ...)
# S4 method for character
checkmnc(file, ...)
# S4 method for list
checkmnc(file, ...)
ensure_mnc(file, ...)
character or nifti object
options passed to checkimg
Character filename of mnc image