"""This is a list of various utility functions used in PyZipline."""
from datetime import datetime as dtime

def convert_str_to_datetime(date_string: str) -> dtime:
    """Converts a Zipline date string to a datetime object

    Args:
        date_string: String to convert

    Returns:
        datetime: Datetime object
    """
    return dtime.strptime(date_string, '%Y-%m-%dT%H:%M:%S.%fZ')

def convert_datetime_to_str(datetime: dtime) -> str:
    """Converts a datetime object to a Zipline (`ISO 8601`) date string

    Args:
        datetime: Datetime to convert

    Returns:
        str: Converted date string
    """
    return datetime.strftime('%Y-%m-%dT%H:%M:%S.%f+00:00')