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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 type(self):
 """Returns 'number', 'string', 'date' or 'unknown' based on the type of the value"""

        if isinstance(self.value, numbers.Number):
            return "number"
        if isinstance(self.value, basestring):
            return "string"
        return "unknown"