def check_overlap(team1, team2):
    """Checks if a player is already in a team.

    Arguments:
        team1 list -- list of summoners on team1
        team2 list -- list of summoners on team2

    Returns:
        boolean -- true if player is in team else false
    """    
    for player1 in team1.player_list:
        for player2 in team2.player_list:
            if player1 == player2:
                return True
    return False