'Initialises the OrderEvent.
Parameters:
ticker - The ticker symbol, e.g. \'GOOG\'.
action - \'BOT\' (for long) or \'SLD\' (for short).
quantity - The quantity of shares to transact.'

def __init__(self, ticker, action, quantity):

    self.type = EventType.ORDER
    self.ticker = ticker
    self.action = action
    self.quantity = quantity
