[Python] Regex Group referencing doesn't work for re.findall() python [duplicate]

I am new to regular expression. I ran into an issue trying group referencing with re.findall() function of python.

Here in pattern i try to group ha --> 1 and haa --> 2 and try to reference it into the itself to avoid repetition.

import re
s = "ha-haa-ha-haa"
re.findall(r"(ha)-(haa)-\1-\2", s)


[('ha', 'haa')] # Actual Output
['ha-haa-ha-haa'] # Expected output


I tried some different approaches:

Approach 1

import re
s = "ha-haa-ha-haa"
p = re.compile(r"(ha)-(haa)-\1-\2")
re.findall(p, s)


Still get this output:


[('ha', 'haa')] # Output


Approach 2

I tried this then:

import re
s = "ha-haa-ha-haa"
p = re.compile(r"(ha)-(haa)-\1-\2")
re.search(p, s)


This gave expected output

<re.Match object; span=(0, 13), match='ha-haa-ha-haa'>


Can somebody explain why group reference is not working for re.findall() while working for re.search()?

I am using python 3.12.11

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