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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 write_to_file(self, filename):
 """Write minimum needs as json to a file. :param filename: The file to be written to. :type filename: basestring, str """

        if not exists(dirname(filename)):
            return -1
        with open(filename, 'w') as fd:
            needs_json = json.dumps(self.minimum_needs)
            fd.write(needs_json)
        return 0