old_contents: const simplifyExpressionNode = require('./lib/simplifyExpressionNode');
  const simplifyExpressionString = require('./lib/simplifyExpressionString');
  const solveEquation = require('./lib/solveEquation/solveEquation');
  const solveEquationString = require('./lib/solveEquation/solveEquationString');
  const MathChangeTypes = require('./lib/MathChangeTypes');
  
  module.exports = {
    // TODO: after deploying this and then the update to Athena.
    // remove expressionStepper
    expressionStepper: simplifyExpressionNode,
    simplifyExpressionString: simplifyExpressionString,
    // TODO: after deploying this and then the update to Athena,
    // remove equationStepper
    equationStepper: solveEquation,
    solveEquationString: solveEquationString,
    MathChangeTypes: MathChangeTypes,
  };
  
new_contents: const simplifyExpressionNode = require('./lib/simplifyExpressionNode');
  const simplifyExpressionString = require('./lib/simplifyExpressionString');
  const solveEquation = require('./lib/solveEquation/solveEquation');
  const solveEquationString = require('./lib/solveEquation/solveEquationString');
  const MathChangeTypes = require('./lib/MathChangeTypes');
  
  module.exports = {
    simplifyExpressionString: simplifyExpressionString,
    solveEquationString: solveEquationString,
    MathChangeTypes: MathChangeTypes,
  };
  
subject: remove old module exports