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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 convert(self, vroot, entry_variables):
 """Convert a given graph. Convert a given graph using the `converters` in the order of the registeration, i.e., sequentially. Args: vroot (:obj:`Variable`):
 NNabla Variable entry_variables (:obj:`Variable`):
 Entry variable from which the conversion starts. """


        for converter in self.converters:
            vroot = converter.convert(vroot, entry_variables)
        return vroot