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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_elastix_exes():
 """ Get the executables for elastix and transformix. Raises an error if they cannot be found. """

    if EXES:
        if EXES[0]:
            return EXES
        else:
            raise RuntimeError('No Elastix executable.')
    
    # Find exe
    elastix, ver = _find_executables('elastix')
    if elastix:
        base, ext = os.path.splitext(elastix)
        base = os.path.dirname(base)
        transformix = os.path.join(base, 'transformix' + ext)
        EXES.extend([elastix, transformix])
        print('Found %s in %r' % (ver, elastix))
        return EXES
    else:
        raise RuntimeError('Could not find Elastix executable. Download '
                           'Elastix from http://elastix.isi.uu.nl/. Pyelastix '
                           'looks for the exe in a series of common locations. '
                           'Set ELASTIX_PATH if necessary.')