{{alias}}( [dtype] )
    Returns a list of array data types to which a provided array data type can
    be safely cast and, for floating-point data types, can be downcast.

    If not provided an array data type, the function returns a casting table.

    If provided an unrecognized array data type, the function returns `null`.

    Parameters
    ----------
    dtype: any (optional)
        Array data type value.

    Returns
    -------
    out: Object|Array<string>|null
        Array data types to which a data type can be cast.

    Examples
    --------
    > var out = {{alias}}( 'float32' )
    <Array>

    See Also
    --------