Decimal.copy_sign

Return a copy of *self* with the sign of *other*.

For example:

    >>> Decimal('2.3').copy_sign(Decimal('-1.5'))
    Decimal('-2.3')

This operation is unaffected by context and is quiet: no flags are
changed and no rounding is performed. As an exception, the C version
may raise InvalidOperation if the second operand cannot be converted
exactly.