{{alias}}( [dtype] )
    Returns the description for a specified data type.

    If not provided a data type value, the function returns an object mapping
    data type strings to descriptions.

    If provided an unknown/unsupported data type, the function returns `null`.

    Parameters
    ----------
    dtype: any (optional)
        Data type value.

    Returns
    -------
    desc: Object|string|null
        Description(s).

    Examples
    --------
    > var out = {{alias}}( 'float64' )
    '...'
    > out = {{alias}}( 'foobar' )
    null
    > out = {{alias}}()
    {...}

    See Also
    --------