[BUG] can not use conditional expression in for loop in the jinja template

[GordonWang]

Describe the bug
when using if/else expression in for loop in jinja template, the for loop does not work.

To Reproduce
Steps to reproduce the behavior:

1. Use the eventgen.conf attached and the jinja template attached.
2. Generate the events with splunk_eventgen command line tool.
3. Check the output events.

Expected behavior
There should be 9 events.

Actual behavior
There are only 3 events. One event for each generator iteration.

Screenshots
N/A

Sample files and eventgen.conf file

Do you run eventgen with SA-eventgen?
No

If you are using eventgen with pip module mode (please complete the following information):

• python version: 2.7
• OS: Mac os 10.14
• Virtual Env is used: Yes/No
• Eventgen Version 6.3.4

Additional context

[GordonWang]

Configuration file content

[test_jinja_template_advance]
end = 1
count = 3
interval = 5
sampleDir = tests/large/sample
jinja_template_dir = tests/large/sample/templates
generator = jinja
jinja_target_template = test_jinja_tmpl_advance.j2
jinja_variables = {"large_number":3, "username": "admim", "flag": true}
earliest = -3s
latest = now
outputMode = stdout

Jinja template file

{% for idx in [1,2,3] %}
{%- time_slice earliest="1234", latest="2345", count=loop.index, slices="5" -%}
{% if flag %}
{"_time":"{{ time_target_epoch }}", "_raw":"{{ time_target_formatted }} [{{username}}] test jinja template generator, switch={{flag}}, seq: {{loop.index}}/{{large_number}}"}
{% else %}
{"_time":"{{ time_target_epoch }}", "_raw":"{{ time_target_formatted }} [{{username}}] test jinja template generator, switch={{flag}}, seq: {{loop.index}}/{{large_number}}"}
{% endif %}
{% endfor %}