code: function assignToGlobal(expr, nodes, expression) {
      createGlobal(expr, nodes);
      if (!t.isExpression(expression)) {
        expression = t.toExpression(expression);
      }
      nodes.push(t.expressionStatement(t.assignmentExpression('=', expr, expression)));
    }
docs: Assigns the given expression to a global with the given id.
  @param {!MemberExpression} expr
  @param {!Array} nodes
  @param {!Expression} expression