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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 _construct_new_key(name, units=None):
 """Construct an MDF safe key from the name and units"""

    to_replace = ["/", "\\", "*", "^", "#", " ", "\n", "\t", ",", ".", ")", "(", "'", "`", "-"]
    to_remove = ["$", "{", "}"]

    cat = name
    if units:
        cat = "_".join([name, units])
    for c in to_replace:
       cat = cat.replace(c, "_")
    for c in to_remove:
       cat = cat.replace(c, "")

    cat = re.sub('_+','_', cat)

    return cat