Try to assign a variable with a new value. A variable is selected randomly, a
different (available) value is randomly selected for the variable -- the variable is
assigned with the new value if there is no conflict.
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it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 3 of the
License, or (at your option) any later version.
This library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.