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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 nma_attribute(self, stmt, p_elem, pset=None):
 """Map `stmt` to a NETMOD-specific attribute. The name of the attribute is the same as the 'keyword' of `stmt`. """

        att = "nma:" + stmt.keyword
        if att not in p_elem.attr:
            p_elem.attr[att] = stmt.arg