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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 find_one(self, filter=None, fields=None, skip=0, sort=None):
 """ Similar to find. This method will only retrieve one row. If no row matches, returns None """

        result = self.find(filter=filter, fields=fields, skip=skip, limit=1, sort=sort)
        if len(result) > 0:
            return result[0]
        else:
            return None