Constructs an SArray of size with a const value.

        Parameters
        ----------
        value : [int | float | str | array.array | list | dict | datetime]
          The value to fill the SArray
        size : int
          The size of the SArray
        dtype : type
          The type of the SArray. If not specified, is automatically detected
          from the value. This should be specified if value=None since the
          actual type of the SArray can be anything.

        Examples
        --------
        Construct an SArray consisting of 10 zeroes:

        >>> turicreate.SArray.from_const(0, 10)

        Construct an SArray consisting of 10 missing string values:

        >>> turicreate.SArray.from_const(None, 10, str)

def from_const(cls, value, size, dtype=type(None)):
        """
        Constructs an SArray of size with a const value.

        Parameters
        ----------
        value : [int | float | str | array.array | list | dict | datetime]
          The value to fill the SArray
        size : int
          The size of the SArray
        dtype : type
          The type of the SArray. If not specified, is automatically detected
          from the value. This should be specified if value=None since the
          actual type of the SArray can be anything.

        Examples
        --------
        Construct an SArray consisting of 10 zeroes:

        >>> turicreate.SArray.from_const(0, 10)

        Construct an SArray consisting of 10 missing string values:

        >>> turicreate.SArray.from_const(None, 10, str)
        """
        assert isinstance(size, (int, long)) and size >= 0, "size must be a positive int"
        if not isinstance(value, (type(None), int, float, str, array.array, list, dict, datetime.datetime)):
            raise TypeError('Cannot create sarray of value type %s' % str(type(value)))
        proxy = UnitySArrayProxy()
        proxy.load_from_const(value, size, dtype)
        return cls(_proxy=proxy)