from textwrap import dedent 
# ...
templated_command = dedent(
"""
{% for i in range(5) %}
    echo "{{ ds }}" #a variable (datestamp)
    echo "{{ macros.ds_add(ds, 7)}}" #a built-in macro
{% endfor %}
"""
)

t3 = BashOperator(
    task_id="templated",
    depends_on_past=False,
    bash_command=templated_command,
)

t2 >> t3