Return the cube root of x.

    For x negative, return a negative number.  The cube root of -0 is defined
    to be -0.

def cbrt(x, context=None):
    """
    Return the cube root of x.

    For x negative, return a negative number.  The cube root of -0 is defined
    to be -0.

    """
    return _apply_function_in_current_context(
        BigFloat,
        mpfr.mpfr_cbrt,
        (BigFloat._implicit_convert(x),),
        context,
    )