def buy(self, security: Security, num_shares: int, online: bool) -> str:
"""
Adds num_shares of the given security to the holdings of this asset
class. Returns the state of the buy transaction.
"""
price: Optional[float] = security.get_price()
if price is None:
raise Exception("Can't buy security with undefined price")
security_id: str = security.get_id()
if self.contains_holding(security_id):
hol: Holding = self.get_holding(security_id)
old_num_shares: int = hol.get_num_shares()
old_abp: float = hol.get_average_buy_price()
old_div: float = hol.get_dividends()
new_num_shares: int = old_num_shares + num_shares
new_abp: float = (old_abp * old_num_shares + price *
num_shares) / (old_num_shares + num_shares)
self.update_holding(security_id, new_num_shares, new_abp, old_div)
else:
self.update_holding(security_id, num_shares, price, 0.0)
log.info("Buy {n} {s} of {c} at {p} for a total of {t}? (Y/n) ".format(
n=num_shares,
s="shares" if num_shares > 1 else "share",
c=security.get_symbol(),
p=dollar_str(price),
t=dollar_str(price * num_shares),
))
order_state: str = "confirmed"
if online:
# Actually buy the ETFs
user_choice: str = input("").lower()
if user_choice in ["", "y"]:
resp: Dict[str,
Any] = r.order_buy_limit(security.get_symbol(),
num_shares,
security.get_price())
if resp is None:
order_state = "failed"
else:
order_state = resp["state"]
return order_state
def __init__(self, security: Security, num_shares: int) -> None:
sec_price = security.get_price()
if sec_price is None:
raise Exception(
"Purchase must be instantiated with a Security "
"that has a non-None price"
)
if num_shares <= 0:
raise Exception(
"Purchase must be instantiated with num_shares >= 0"
)
self.__security: Security = security
self.__num_shares: int = num_shares
self.__cost: float = sec_price * self.__num_shares