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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 delcal(mspath):
 """Delete the ``MODEL_DATA`` and ``CORRECTED_DATA`` columns from a measurement set. mspath (str) The path to the MS to modify Example:: from pwkit.environments.casa import tasks tasks.delcal('dataset.ms') """

    wantremove = 'MODEL_DATA CORRECTED_DATA'.split()
    tb = util.tools.table()
    tb.open(b(mspath), nomodify=False)
    cols = frozenset(tb.colnames())
    toremove = [b(c) for c in wantremove if c in cols]
    if len(toremove):
        tb.removecols(toremove)
    tb.close()

    # We want to return a `str` type, which is what we already
    # have in Python 2 but not in 3.
    if six.PY2:
        return toremove
    else:
        return [c.decode('utf8') for c in toremove]