presto-main/src/main/java/io/prestosql/metadata/BoundVariables.java/BoundVariables/getValue
class BoundVariables:    private static <T> T getValue(Map<String, T> map, String variableName)
    {
        checkState(variableName != null, "variableName is null");
        T value = map.get(variableName);
        checkState(value != null, "value for variable '%s' is null", variableName);
        return value;
    }