Source code for langchain.output_parsers.datetime
import random
from datetime import datetime, timedelta
from typing import List
from langchain.schema import BaseOutputParser, OutputParserException
from langchain.utils import comma_list
def _generate_random_datetime_strings(
    pattern: str,
    n: int = 3,
    start_date: datetime = datetime(1, 1, 1),
    end_date: datetime = datetime.now() + timedelta(days=3650),
) -> List[str]:
    """Generates n random datetime strings conforming to the
    given pattern within the specified date range.
    Pattern should be a string containing the desired format codes.
    start_date and end_date should be datetime objects representing
    the start and end of the date range.
    """
    examples = []
    delta = end_date - start_date
    for i in range(n):
        random_delta = random.uniform(0, delta.total_seconds())
        dt = start_date + timedelta(seconds=random_delta)
        date_string = dt.strftime(pattern)
        examples.append(date_string)
    return examples
[docs]class DatetimeOutputParser(BaseOutputParser[datetime]):
    """Parse the output of an LLM call to a datetime."""
    format: str = "%Y-%m-%dT%H:%M:%S.%fZ"
    """The string value that used as the datetime format."""
[docs]    def get_format_instructions(self) -> str:
        examples = comma_list(_generate_random_datetime_strings(self.format))
        return f"""Write a datetime string that matches the 
            following pattern: "{self.format}". Examples: {examples}"""
[docs]    def parse(self, response: str) -> datetime:
        try:
            return datetime.strptime(response.strip(), self.format)
        except ValueError as e: