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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 make_opfields( cls ):
 """ Calculate the virtulachain-required opfields dict. """

        # construct fields 
        opfields = {}
        for opname in SERIALIZE_FIELDS.keys():
            opcode = NAME_OPCODES[opname]
            opfields[opcode] = SERIALIZE_FIELDS[opname]

        return opfields