def time_difference(time_start, time_end):
    '''Calculate the difference between two times on the same date.

    Args:
        time_start: the time to use as a starting point
        time_end: the time to use as an end point

    Returns:
        the difference between time_start and time_end. For example:

        >>> time_difference(1500, 1600)
        60

        >>> time_difference(1100, 1310)
        130

    Raises:
        TypeError: if time_start and time_end is not a string
        ValueError: if time_start and time_end is below 0 or above 2400
    '''

    try:
        if not isinstance(time_start, str):
            raise TypeError('time_start has to be a string!')
        elif not isinstance(time_end, str):
            raise TypeError('time_end has to be a string!')
        elif int(time_start) > 2400 or int(time_end) < 0:
            raise ValueError('time_start nor time_end can be below 0 or above 2400!')
        elif int(time_start) > int(time_end):
            raise ValueError('time_start cannot be higher than time_end!')
    except (TypeError, ValueError):
        raise

    # Convert time_start and time_end to necessary variables
    # for the calculation.
    hours_begin = time_start[0] + time_start[1]
    minutes_begin = time_start[2] + time_start[3]
    hours_end = time_end[0] + time_end[1]
    minutes_end = time_end[2] + time_end[3]

    # Calculates the difference.
    minutes = ((int(hours_end) - int(hours_begin)) * 60 +
        int(minutes_end) - int(minutes_begin))

    return(minutes)

from datetime import datetime

def time_difference(time_start, time_end):
    '''Calculate the difference between two times on the same date.

    Args:
        time_start: the time to use as a starting point
        time_end: the time to use as an end point

    Returns:
        the difference between time_start and time_end. For example:

        >>> time_difference('1500', '1600')
        60

        >>> time_difference('1100', '1310')
        130
    '''

    start = datetime.strptime(time_start, "%H%M")
    end = datetime.strptime(time_end, "%H%M")
    difference = end - start
    minutes = difference.total_seconds() / 60
    return int(minutes)