{% for i in range((last_day-first_day).days + 1) %}
{% set day_date = first_day + timedelta(days=i) %}
{% set workout =
get_first_element_from_list_with_matching_attribute(person['Workouts'],
'StartDate',
day_date) %}
{% set is_in_month = day_date.month == first_day_of_month.month%}
{% if is_in_month %}
{{ day_date.day }} {% endif %}
{% endfor %}