code: public TemplateInstanceExecution templateInstanceExecution(String sourceName, ExpressionEngine expressionEngine) {
          // Transforms each parameter in a name/value pair, using only the source name as input
          Map<String, String> sourceNameInput = Collections.singletonMap("sourceName", sourceName);
          Map<String, String> parameterMap = Maps.transformValues(
                  Maps.uniqueIndex(
                          parameters,
                          TemplateParameter::getName
                  ),
                  parameter -> expressionEngine.render(parameter.getExpression(), sourceNameInput)
          );
          // Concatenates the maps
          Map<String, String> inputMap = new HashMap<>(sourceNameInput);
          inputMap.putAll(parameterMap);
          // Resolves the final expression
          return new TemplateInstanceExecution(
                  value -> expressionEngine.render(value, inputMap),
                  parameterMap
          );
      }
docs: Gets the execution context for the creation of a template instance.
  
  @param sourceName       Input for the expression
  @param expressionEngine Expression engine to use
  @return Transformed string