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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 get_minimum_span(low, high, span):
 """ If lower and high values are equal ensures they are separated by the defined span. """

    if is_number(low) and low == high:
        if isinstance(low, np.datetime64):
            span = span * np.timedelta64(1, 's')
        low, high = low-span, high+span
    return low, high