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python importlib.import_module requires explicitly imported module

i want to implement sort of plugin architecture that dynamically loads modules and calls a function from them
for instance plugin code looks like (in file "foo_func.py")
foo_local = []
def foo_add(a: int, b: int) -> int:
c = a + b
foo_local.append(c)
return c
def foo_print():
print(foo_local)
i need to support two plugins with the same code but with different memory state, so i created directory structure like this:
<ROOT_PROJECT>
app.py
bar/
apple/
foo/
foo_func.py
__init__.py
orange/
foo/
foo_func.py
__init__.py
code in "apple" and "orange" folders is the same.
then in app file i try to load modules and invoke functions from them
import importlib
from bar.apple.foo.foo_func import foo_add as apple_foo_add, foo_print as apple_foo_print
from bar.orange.foo.foo_func import foo_add as orange_foo_add, foo_print as orange_foo_print
apple = importlib.import_module('bar.apple.foo')
orange = importlib.import_module('bar.orange.foo')
apple_foo = getattr(apple, 'foo_func')
orange_foo = getattr(orange, 'foo_func')
apple_foo_add_my = getattr(apple_foo, 'foo_add')
apple_foo_print_my = getattr(apple_foo, 'foo_print')
apple_foo_add_my(1, 2)
apple_foo_print_my()
and this works fine, but you see these import lines at the top
from bar.apple.foo.foo_func import foo_add as apple_foo_add, foo_print as apple_foo_print
from bar.orange.foo.foo_func import foo_add as orange_foo_add, foo_print as orange_foo_print
they are not used in code (even pycharm complains about it)
but if i try to comment code and run it - then failure
AttributeError: module 'bar.apple.foo' has no attribute 'foo_func'
why ?
I suppose normal plugins should deal only with "importlib.import_module" and "getattr" and it must be enough ?
what is wrong here ?

Let's switch completely to direct imports for this explanation, because:
import something.whatever as name
is the same as:
name = importlib.import_module("something.whatever")
So let's rewrite your apple code:
apple = importlib.import_module('bar.apple.foo')
apple_foo = getattr(apple, 'foo_func')
will become:
import bar.apple.foo as apple
apple_foo = apple.foo_func
Now, the first line loads bar.apple.foo as a module. In case of packages, this means importing package's __init__.py code. And treating it as a module itself.
And what's the code in the package's init? Usually nothing! That's why the name lookup fails.
However, when you do any import my_package.whatever, the package gets its insides checked and the name becomes visible. You're basically pre-loading the module for interpreter to look at.
Why is pycharm giving you not used suggestion? Because it's not used as a variable anywhere. You're only using a side-effect + pycharm doesn't analyze strings for imports or attributes.
Visual example, with a part of standard library:
>>> import xml
>>> dir(xml)
['__all__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__path__', '__spec__']
>>> xml.etree
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: module 'xml' has no attribute 'etree'
>>>
>>> import xml.etree
>>> dir(xml)
['__all__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__path__', '__spec__', 'etree']
And another example, what happens if there are multiple modules in the package:
>>> import dateutil
>>> dir(dateutil)
['__all__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__path__', '__spec__', '__version__', '_version']
but:
>>> import dateutil.parser
>>> dir(dateutil)
['__all__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__path__', '__spec__', '__version__', '_common', '_version', 'parser', 'relativedelta', 'tz']
All sub-modules are now visible and usable with their qualified name.
tl;dr: import my_package == only my_package/__init__.py is looked at. import my_package.whatever == python now knows it's a package and registers its insides, all modules of my_package are visible and usable.

pygame.time.Clock() function not working on Ubuntu18.04

I am using ubuntu18.04. I have installed pygame module to play songs. But the time.Clock() function is not working. It is showing this following error after running the program: AttributeError: 'function' object has no attribute 'Clock'.
Here is the code:
def playSong(filename):
mixer.init()
mixer.music.load('/home/mjiabir/Music/rangamati songs/Roar.mp3')
mixer.music.play()
while mixer.music.get_busy:
time.Clock.tick(10)
mixer.music.stop()
Looks like Linux doesn't support this module. What should I do now?

I think you want to use pygame.time.Clock().tick(10).
One way to look up modules of a package or sub-package is to use dir(). For example:
# in a python interactive shell
import time
dir(time)
# output => ['CLOCK_BOOTTIME', 'CLOCK_MONOTONIC', 'CLOCK_MONOTONIC_RAW', 'CLOCK_PROCESS_CPUTIME_ID', 'CLOCK_REALTIME', 'CLOCK_THREAD_CPUTIME_ID', '_STRUCT_TM_ITEMS', '__doc__', '__loader__', '__name__', '__package__', '__spec__', 'altzone', 'asctime', 'clock', 'clock_getres', 'clock_gettime', 'clock_gettime_ns', 'clock_settime', 'clock_settime_ns', 'ctime', 'daylight', 'get_clock_info', 'gmtime', 'localtime', 'mktime', 'monotonic', 'monotonic_ns', 'perf_counter', 'perf_counter_ns', 'process_time', 'process_time_ns', 'pthread_getcpuclockid', 'sleep', 'strftime', 'strptime', 'struct_time', 'thread_time', 'thread_time_ns', 'time', 'time_ns', 'timezone', 'tzname', 'tzset']
import pygame
dir(pygame.time)
# output => ['Clock', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', 'delay', 'get_ticks', 'set_timer', 'wait']

Although you can use pygame.time.Clock().tick(), I would suggest constructing a Clock object, through clock = pygame.time.Clock() and clock.tick(10). Generally, it is good practice to utilize the object-oriented nature of Python, as opposed to calling construct methods directly.

How to make Python find a file in script mode?

I'm currently trying to import Python files downloaded from external sources into my code. This has worked perfectly fine within the Python shell, but when using the exact same code within an IDLE file, Python is unable to find the file in the given directory, even though it does find the directory itself.
My aim is to import the Python Natural Language Toolkit, which requires the module 'six'. So I've imported first 'six', then NLTK into a shell.
I've then tried to repeat the same code within script mode.
INTERACTIVE MODE
>>> import os
>>> path = "C:/Users/henri/AppData/Local/Programs/Python/Python37-32/lib/site-packages/pip/_vendor/urllib3/packages"
>>> os.chdir(path)
>>> os.getcwd()
Result:
'C:\\Users\\henri\\AppData\\Local\\Programs\\Python\\Python37-32\\lib\\site-packages\\pip\\_vendor\\urllib3\\packages' <br/>
>>> import six
>>> dir(six)
Result:
['BytesIO', 'Iterator', 'MAXSIZE', 'Module_six_moves_urllib', 'Module_six_moves_urllib_error', 'Module_six_moves_urllib_parse', 'Module_six_moves_urllib_request', 'Module_six_moves_urllib_response', 'Module_six_moves_urllib_robotparser', 'MovedAttribute', 'MovedModule', 'PY2', 'PY3', 'PY34', 'StringIO', '_LazyDescr', '_LazyModule', '_MovedItems', '_SixMetaPathImporter', '__author__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__path__', '__spec__', '__version__', '_add_doc', '_assertCountEqual', '_assertRaisesRegex', '_assertRegex', '_func_closure', '_func_code', '_func_defaults', '_func_globals', '_import_module', '_importer', '_meth_func', '_meth_self', '_moved_attributes', '_urllib_error_moved_attributes', '_urllib_parse_moved_attributes', '_urllib_request_moved_attributes', '_urllib_response_moved_attributes', '_urllib_robotparser_moved_attributes', 'absolute_import', 'add_metaclass', 'add_move', 'advance_iterator', 'assertCountEqual', 'assertRaisesRegex', 'assertRegex', 'b', 'binary_type', 'byte2int', 'callable', 'class_types', 'create_bound_method', 'create_unbound_method', 'exec_', 'functools', 'get_function_closure', 'get_function_code', 'get_function_defaults', 'get_function_globals', 'get_method_function', 'get_method_self', 'get_unbound_function', 'indexbytes', 'int2byte', 'integer_types', 'io', 'iterbytes', 'iteritems', 'iterkeys', 'iterlists', 'itertools', 'itervalues', 'moves', 'next', 'operator', 'print_', 'python_2_unicode_compatible', 'raise_from', 'remove_move', 'reraise', 'string_types', 'sys', 'text_type', 'types', 'u', 'unichr', 'viewitems', 'viewkeys', 'viewvalues', 'with_metaclass', 'wraps']
SCRIPT MODE
import os
# importing six
path="C:/Users/henri/AppData/Local/Programs/Python/Python37-32/lib/site-packages/pip/_vendor/urllib3/packages"
os.chdir(path)
os.getcwd()
print(os.getcwd())
import six
dir(six)
And this is the resulting error message when trying to run this code:
RESTART: C:\Users\henri\AppData\Local\Programs\Python\Python37-32\importing_nltk_file_2.py
C:\Users\henri\AppData\Local\Programs\Python\Python37-32\lib\site-packages\pip_vendor\urllib3\packages
Traceback (most recent call last):
File "C:\Users\henri\AppData\Local\Programs\Python\Python37-32\importing_nltk_file_2.py", line 13, in
import six
ModuleNotFoundError: No module named 'six'
So, does anyone have an idea why Python can't find 'six', although the directory is unmistakeably correct?

when you run a python script all import statements are run first and then other parts of your code are executed. So, import six is executed before os.chdir() and hence, the error

mpl_finance module import error in python

I have tried using from matplotlib.finance import quotes_historical_yahoo_ochl but found that it is deprecated. Hence, I have installed mpl_finance and tried this:
from mpl_finance import quotes_historical_yahoo_ochl
But I got the following error:
ImportError: cannot import name 'quotes_historical_yahoo_ochl'
I thought to check it:
dir(mpl_finance)
And found the following:
['Affine2D', 'Line2D', 'LineCollection', 'PolyCollection', 'Rectangle', 'TICKLEFT', 'TICKRIGHT', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', '_candlestick', '_check_input', '_plot_day_summary', 'absolute_import', 'candlestick2_ochl', 'candlestick2_ohlc', 'candlestick_ochl', 'candlestick_ohlc', 'division', 'index_bar', 'mcolors', 'np', 'plot_day_summary2_ochl', 'plot_day_summary2_ohlc', 'plot_day_summary_oclh', 'plot_day_summary_ohlc', 'print_function', 'unicode_literals', 'volume_overlay', 'volume_overlay2', 'volume_overlay3', 'xrange', 'zip']
Kindly, help me get rid of this issue. Please.

Because yahoo has ceased to provide its historical quotes service, the quotes_historical_yahoo_ochl function stopped working. It was hence removed from the mpl_finance code completely.

Python - submodule loading detection

I am currently working on a library that patches several other modules upon loading. It mostly works fine, however in some cases it runs into the problem when the functions to be patched are contained in a sub-module that needs to be explicitely loaded. For instance in scikits-learn, the sub-module datasets has the following behavior:
>>> import sklearn
>>> dir(sklearn)
['__SKLEARN_SETUP__', '__all__', '__builtins__', '__check_build', '__doc__', '__file__', '__name__', '__package__', '__path__', '__version__', 'base', 'clone', 'externals', 're', 'setup_module', 'sys', 'utils', 'warnings']
It only loads it in case when dataset was explicitely loaded:
>>> from sklearn import datasets
>>> dir(sklearn)
['__SKLEARN_SETUP__', '__all__', '__builtins__', '__check_build', '__doc__', '__file__', '__name__', '__package__', '__path__', '__version__', 'base', 'clone', 'datasets', 'externals', 'feature_extraction', 'preprocessing', 're', 'setup_module', 'sys', 'utils', 'warnings']
How can I detect when dataset is explicitely imported in order to launch my patching only when this sub-module is loaded?