How to use the @dataform/core/tasks.Tasks.create function in @dataform/core

public publishTasks(
    table: dataform.ITable,
    runConfig: dataform.IRunConfig,
    tableMetadata: dataform.ITableMetadata
  ): Tasks {
    const tasks = Tasks.create();
    // Drop the existing view or table if we are changing its type.
    if (tableMetadata && tableMetadata.type !== this.baseTableType(table.type)) {
      tasks.add(
        Task.statement(this.dropIfExists(table.target, this.oppositeTableType(table.type)))
      );
    }
    if (table.type === "incremental") {
      if (runConfig.fullRefresh || !tableMetadata || tableMetadata.type === "view") {
        tasks.addAll(this.createOrReplace(table, !!tableMetadata));
      } else {
        // The table exists, insert new rows.
        tasks.add(
          Task.statement(
            this.insertInto(
              table.target,
              tableMetadata.fields.map(f => f.name),

public publishTasks(
    table: dataform.ITable,
    runConfig: dataform.IRunConfig,
    tableMetadata: dataform.ITableMetadata
  ): Tasks {
    const tasks = Tasks.create();
    // Drop the existing view or table if we are changing it's type.
    if (tableMetadata && tableMetadata.type != this.baseTableType(table.type)) {
      tasks.add(
        Task.statement(this.dropIfExists(table.target, this.oppositeTableType(table.type)))
      );
    }
    if (table.type == "incremental") {
      if (runConfig.fullRefresh || !tableMetadata || tableMetadata.type == "view") {
        tasks.add(Task.statement(this.createOrReplace(table)));
      } else {
        // The table exists, insert new rows.
        tasks.add(
          Task.statement(
            this.insertInto(
              table.target,
              tableMetadata.fields.map(f => f.name),

public assertTasks(
    assertion: dataform.IAssertion,
    projectConfig: dataform.IProjectConfig
  ): Tasks {
    const tasks = Tasks.create();
    const target =
      assertion.target ||
      dataform.Target.create({
        schema: projectConfig.assertionSchema,
        name: assertion.name
      });
    tasks.add(Task.statement(this.createOrReplaceView(target, assertion.query)));
    tasks.add(Task.assertion(`select sum(1) as row_count from ${this.resolveTarget(target)}`));
    return tasks;
  }

private createOrReplace(table: dataform.ITable, alreadyExists: boolean) {
    if (table.type === "view") {
      return Tasks.create().add(
        Task.statement(
          `${alreadyExists ? "alter" : "create"} view ${this.resolveTarget(table.target)} as ${
            table.query
          }`
        )
      );
    }
    const tempTableTarget = dataform.Target.create({
      schema: table.target.schema,
      name: table.target.name + "_temp"
    });

    return Tasks.create()
      .add(Task.statement(this.dropIfExists(tempTableTarget, this.baseTableType(table.type))))
      .add(Task.statement(this.createTable(table, tempTableTarget)))
      .add(Task.statement(this.dropIfExists(table.target, "table")))

public assertTasks(
    assertion: dataform.IAssertion,
    projectConfig: dataform.IProjectConfig
  ): Tasks {
    const target =
      assertion.target ||
      dataform.Target.create({
        schema: projectConfig.assertionSchema,
        name: assertion.name
      });

    return Tasks.create()
      .add(Task.statement(this.dropIfExists(target, "view")))
      .add(
        Task.statement(`
        create view ${this.resolveTarget(target)}
        as ${assertion.query}`)
      )
      .add(Task.assertion(`select sum(1) as row_count from ${this.resolveTarget(target)}`));
  }