Do packages really require "__init__.py" ?

[snippsat]

Python recognises "package" as being a package event without the presence of the file "__init__.py".

Do I misunderstand something ?

No,from Python 3.3+ supports Implicit Namespace Packages that allows to create a package without an __init__.py file.
This however only applies to empty __init__.py files.
So empty __init__.py files are no longer necessary and can be omitted.

To give a example,i always have one __init__.py that has content to lift sub modules,
this to avoid long import statement and make it easier for users of package.

my_pack\
|-- __init__.py
  color\
  |-- base_color.py
    gradient\    
    |-- gradient.py

__init__.py

from .color import base_color
from .color.gradient import gradient

base_color.py

def red():
    return 'rgb(255, 0, 0)'

gradient.py

def hsl_value():
    return 'rgba(255, 100, 50, 1.0)'

As i have lifted with __init__.py there is no need to say color.gradient.hsl_value() when import.
Usage:

λ ptpython
>>> from my_pack import base_color, gradient

>>> base_color.red()
'rgb(255, 0, 0)'


>>> gradient.hsl_value()
'rgba(255, 100, 50, 1.0)'

And stop using very old %s string formatting.

>>> for word in 'f-strings are awesome'.split():
...     print(f'{word.upper():~^20}')
~~~~~F-STRINGS~~~~~~
~~~~~~~~ARE~~~~~~~~~
~~~~~~AWESOME~~~~~~~

>>> # f-strings support any Python expressions inside the curly braces
>>> name = 'f-string'
>>> print(f"My cool string is called {name.upper()}.")
My cool string is called F-STRING.
 
>>> a, b = 5, 7
>>> f'{a}/{b} = {a/b:.2}'
'5/7 = 0.71'