def get_character(line_number, character_position, text):
    """
    Returns character in position (line_number, character_position).
    If there is no character (if the position is "outside" the text),
    function returns None.
    """
    if line_number < 0 or character_position < 0:
        return None
    lines = text.split('\n')
    try:
        return lines[line_number][character_position]
    except IndexError:
        return None
