Parse the text of a .env file to a dictionary of environment variables using only the Python standard library. IMUBVHCIO*, the list/dict comprehensions perfectly straddle the line between an elegant use of syntax and an infinitely dense mass of code (the dreaded "neutron star effect"). And extra bonus: Type hints!

dotenv_parser.py

"""Parse .env file to a dictionary of environment variables."""
import errno
import os
from pathlib import Path
from typing import Dict, List


def parse_dotenv_file(filepath: Path) -> Dict[str, str]:
    """Parse .env file to a dictionary of environment variables."""
    if not filepath.exists():
        raise FileNotFoundError(errno.ENOENT, os.strerror(errno.ENOENT), filepath)
    if not filepath.is_file():
        raise TypeError(f"Unable to open file: {filepath}")

    def sanitize_string(input: str) -> str:
        return input.strip('"').strip("'").strip()

    def parse_env_var_strings(filepath: Path) -> List[List[str]]:
        return [
            s.split("=") for s in [f for f in filepath.read_text().split("\n") if f and "=" in f]
        ]

    return {v[0]: sanitize_string(v[1]) for v in parse_env_var_strings(filepath) if len(v) == 2}

* IMUBVHCIO = In My Unassailable But Very Humble and Completely Impartial Opinion