Python 3.8 sys.getrefcount() returns 5 on first call - python-3.8

Question

Why does this print 5? Using python 3.8. I understand sys.getrefcount() returns a value 1 greater than expected, but 5 ?
from sys import getrefcount
class Foo():
def __del__(self):
print('__del__() called')
print(getrefcount(Foo)) # 5

Answer 1

Interesting one!!
I used the following script to get the list of referrers
import gc
import pprint
import sys
class Example:
def __del__(self):
print("__del__() is called")
if __name__ == "__main__":
reference_count = sys.getrefcount(Example)
print(f"Reference count is {reference_count}")
pretty = pprint.PrettyPrinter(indent=4)
for referrer in gc.get_referrers(Example):
if isinstance(referrer, dict):
pretty.pprint(referrer)
continue
pretty.pprint(referrer)
Here is the output
➜ python3.8 reference_count.py
Reference count is 5
<attribute '__dict__' of 'Example' objects>
<attribute '__weakref__' of 'Example' objects>
(<class '__main__.Example'>, <class 'object'>)
{ 'Example': <class '__main__.Example'>,
'__annotations__': {},
'__builtins__': <module 'builtins' (built-in)>,
'__cached__': None,
'__doc__': None,
'__file__': 'temp.py',
'__loader__': <_frozen_importlib_external.SourceFileLoader object at 0x1006d4550>,
'__name__': '__main__',
'__package__': None,
'__spec__': None,
'gc': <module 'gc' (built-in)>,
'pprint': <module 'pprint' from '/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/pprint.py'>,
'pretty': <pprint.PrettyPrinter object at 0x1006e29d0>,
'reference_count': 4,
'referrer': <Recursion on dict with id=4301742016>,
'sys': <module 'sys' (built-in)>}
Since sys.getrefcount() returns a value 1 grater than the expected, it verifies the length of list of referrers.
Correction
The point to be noted in the question is we have not really called reference count of the Example object, hence __del__ is never called, here is a slightly different example.
...
reference_count = sys.getrefcount(Example())
...
for referrer in gc.get_referrers(Example()):
...
Here is the output
__del__() is called
Reference count is 1
__del__() is called