import time
from datetime import datetime, timedelta


def get_current_time():
    """Returns the current time in seconds since the epoch."""
    return time.time()


def generate_timestrings(start_time_str, end_time_str, dt):
    """Generates a list of timestamps from start_time to end_time, which are strings such
    as 19:00."""

    timestamps = []
    current_time = datetime.strptime(start_time_str, "%H:%M")
    end_time = datetime.strptime(end_time_str, "%H:%M")
    while current_time <= end_time:
        timestamps.append(current_time)
        current_time += timedelta(seconds=dt)
    timestrings = [dt.strftime("%H:%M") for dt in timestamps]
    return timestrings