How can I do validation for datetime input component?

I want to check whether user picked date from datetime input component on a button click
I tried following codes:
if isNull(self.session.custom.expenseSelectDate):
if self.session.custom.expenseSelectDate == null:
if self.session.custom.expenseSelectDate == “null”:
if self.session.custom.expenseSelectDate == “”:
if self.session.custom.expenseSelectDate == 0:

none of them seems wokring

Thank you.

Try just if self.session.custom.expenseSelectDate:.
Python uses the special singleton instance None to represent no value/null.
Literal null is a syntax error unless you’ve defined a variable null in scope.
== "null" is comparing against the literal string "null".
== "" is comparing against an empty string.
== 0 is checking for exact equality with 0; not a ‘falsey’ comparison.

If you omit all operators, Python’s if statement automatically checks for ‘truth’; the following statements are essentially equivalent:

x = 1
if True:
if x:
if x == True:
if bool(x):
if bool(x) == True:

Python’s None singleton is ‘falsey’, so you can simply:

if x:

Which will fail if x is None. Or, the recommended style, which is more explicit:

if x is not None:


Still not working

You might want to add some logging so you can see what you really have in self.session.custom.expenseSelectDate.

Its changing color as required on submit since its checking for true condition i want to check for false condition, how can i do that ?


its null in log there were no errors

Use not:

if not self.session.custom.expenseSelectDate:
    # do something if it's not set
1 Like

this worked for me:

if self.session.custom.expenseSelectDate is None:

Thank you

1 Like