Some Imports are extremely slow (~3 seconds to import)

[drorIvry]

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Describe the bug
A clear and concise description of what the bug is.

some imports are very slow

from google.adk.models import LLMRegistry, BaseLlm
from google.adk.models.lite_llm import LiteLlm

takes a lot of time on first import here is a screenshot from profiling it.

To Reproduce
Please share a minimal code and data to reproduce your problem.
Steps to reproduce the behavior:

1. pip install -U google-adk - I ran on google-adk==1.15.1
2. run the following code:

import time
start_time = time.time()

from google.adk.models import LLMRegistry, BaseLlm
from google.adk.models.lite_llm import LiteLlm

end_time = time.time()
print(f"Time taken: {end_time - start_time} seconds")

WITH PROFILING

import cProfile
import pstats
from io import StringIO

pr = cProfile.Profile()
pr.enable()


import time
start_time = time.time()

from google.adk.models import LLMRegistry, BaseLlm
from google.adk.models.lite_llm import LiteLlm

end_time = time.time()
print(f"Time taken: {end_time - start_time} seconds")

pr.disable()
s = StringIO()
sortby = 'cumulative'
ps = pstats.Stats(pr, stream=s).sort_stats(sortby)

# Save the profiling stats to a file
ps.dump_stats('profile_stats.prof')

3. this already reproduces the issue but to open the profile file I used snakeviz

snakeviz profile_stats.prof

Expected behavior
A clear and concise description of what you expected to happen.
The import shouldn't take so long

Screenshots
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Desktop (please complete the following information):

• OS: macos
• Python version(python -V): 3.11.5
• ADK version(pip show google-adk):1.15.1

Model Information:

• Are you using LiteLLM: Yes but this happens with other imports like LLMRegistry
• Which model is being used - N/A

Additional context
Add any other context about the problem here.