Optimistic‑Pessimistic Evaluator

A lightweight Python package that lets you compare optimistic and pessimistic validation strategies for any textual description or data snippet.
It builds structured prompts, queries a language model, matches the response against a strict regex pattern, and returns a clear, machine‑readable report indicating which approach performs better based on your criteria.

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Installation

pip install optimistic_pessimistic_evaluator

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Quick Start

from optimistic_pessimistic_evaluator import optimistic_pessimistic_evaluator

user_input = """
A user uploads a file. The system checks the file size and type.
We want to know whether an optimistic (early‑exit) or a pessimistic (full‑check) approach is more efficient.
"""

# Use the default LLM7 instance (you need an API key in LLM7_API_KEY env var)
report = optimistic_pessimistic_evaluator(user_input)

print(report)

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Parameters

Parameter	Type	Description
user_input	str	The text to be evaluated.
llm (optional)	BaseChatModel	Any LangChain‑compatible chat model. If omitted, the package creates a ChatLLM7 instance automatically.
api_key (optional)	str	API key for LLM7. If not supplied, the function reads LLM7_API_KEY from the environment.

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Using a Custom LLM

You can pass any LangChain chat model (OpenAI, Anthropic, Google, …). Example with OpenAI:

from langchain_openai import ChatOpenAI
from optimistic_pessimistic_evaluator import optimistic_pessimistic_evaluator

my_llm = ChatOpenAI(model="gpt-4o-mini")
report = optimistic_pessimistic_evaluator(user_input, llm=my_llm)

Anthropic:

from langchain_anthropic import ChatAnthropic
from optimistic_pessimistic_evaluator import optimistic_pessimistic_evaluator

my_llm = ChatAnthropic()
report = optimistic_pessimistic_evaluator(user_input, llm=my_llm)

Google Gemini:

from langchain_google_genai import ChatGoogleGenerativeAI
from optimistic_pessimistic_evaluator import optimistic_pessimistic_evaluator

my_llm = ChatGoogleGenerativeAI(model="gemini-1.5-flash")
report = optimistic_pessimistic_evaluator(user_input, llm=my_llm)

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Default LLM (LLM7)

If you do not provide a custom model, the function uses ChatLLM7 from the langchain_llm7 package:

from langchain_llm7 import ChatLLM7

The free tier of LLM7 offers generous rate limits for typical evaluation workloads.
To use a custom key:

report = optimistic_pessimistic_evaluator(user_input, api_key="YOUR_LLM7_API_KEY")

You can obtain a free API key by signing up at https://token.llm7.io/.

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Output

The function returns a List[str] containing the extracted data that matches the predefined regex pattern, e.g.:

[
  "Optimistic approach is faster for low‑traffic scenarios.",
  "Pessimistic approach provides higher reliability under load."
]

If the LLM call fails or the output does not match the pattern, a RuntimeError is raised with the underlying error message.

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Contributing

Contributions are welcome! Feel free to open a pull request or submit an issue.

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Issues & Support

Report bugs or request features here: https://github.com/chigwell/optimistic-pessimistic-evaluator/issues

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Author

Eugene Evstafev – hi@eugene.plus
GitHub: chigwell

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License

This project is licensed under the MIT License.