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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 where(cls, condition, istrue, isfalse, dtype=None):
 """ Selects elements from either istrue or isfalse depending on the value of the condition SArray. Parameters condition : SArray An SArray of values such that for each value, if non-zero, yields a value from istrue, otherwise from isfalse. istrue : SArray or constant The elements selected if condition is true. If istrue is an SArray, this must be of the same length as condition. isfalse : SArray or constant The elements selected if condition is false. If istrue is an SArray, this must be of the same length as condition. dtype : type The type of result SArray. This is required if both istrue and isfalse are constants of ambiguous types. Examples -------- Returns an SArray with the same values as g with values above 10 clipped to 10 dtype: int Rows: 8 [6, 7, 8, 9, 10, 10, 10, 10] Returns an SArray with the same values as g with values below 10 clipped to 10 dtype: int Rows: 8 [10, 10, 10, 10, 10, 11, 12, 13] Returns an SArray with the same values of g with all values == 1 replaced by None dtype: int Rows: 8 [None, 2, 3, 4, None, 2, 3, 4] Returns an SArray with the same values of g, but with each missing value replaced by its corresponding element in replace_none dtype: int Rows: 4 [1, 2, 2, 2] """

        true_is_sarray = isinstance(istrue, SArray)
        false_is_sarray = isinstance(isfalse, SArray)
        if not true_is_sarray and false_is_sarray:
            istrue = cls(_proxy=condition.__proxy__.to_const(istrue, isfalse.dtype))
        if true_is_sarray and not false_is_sarray:
            isfalse = cls(_proxy=condition.__proxy__.to_const(isfalse, istrue.dtype))
        if not true_is_sarray and not false_is_sarray:
            if dtype is None:
                if istrue is None:
                    dtype = type(isfalse)
                elif isfalse is None:
                    dtype = type(istrue)
                elif type(istrue) != type(isfalse):
                    raise TypeError("true and false inputs are of different types")
                elif type(istrue) == type(isfalse):
                    dtype = type(istrue)
            if dtype is None:
                raise TypeError("Both true and false are None. Resultant type cannot be inferred.")
            istrue = cls(_proxy=condition.__proxy__.to_const(istrue, dtype))
            isfalse = cls(_proxy=condition.__proxy__.to_const(isfalse, dtype))
        return cls(_proxy=condition.__proxy__.ternary_operator(istrue.__proxy__, isfalse.__proxy__))