explicit_vs_verbose.py

from datetime import datetime

def fetch_dates__EMEA() -> dict:
   return {
       "a": "31/1/2000",
       "b": "28/2/2010",
       "c": "30/3/2020",
   }

def fetch_dates__US() -> dict:
   return {
       "a": "1/31/2000",
       "b": "2/28/2010",
       "c": "3/30/2020",
   }

def a__US(fetch_dates__US: dict) -> datetime:
   return datetime.strptime(fetch_dates__US["a"], "%m/%d/%Y")

def b__US(fetch_dates__US: dict) -> datetime:
   return datetime.strptime(fetch_dates__US["b"], "%m/%d/%Y")

def c__US(fetch_dates__US: dict) -> datetime:
   return datetime.strptime(fetch_dates__US["c"], "%m/%d/%Y")

def a__EMEA(fetch_dates__EMEA: dict) -> datetime:
   return datetime.strptime(fetch_dates__EMEA["a"], "%d/%m/%Y")

def b__EMEA(fetch_dates__EMEA: dict) -> datetime:
   return datetime.strptime(fetch_dates__EMEA["b"], "%d/%m/%Y")


def c__EMEA(fetch_dates__EMEA: dict) -> datetime:
   return datetime.strptime(fetch_dates__EMEA["c"], "%d/%m/%Y")

def ab_period(
   a__US: datetime, b__US: datetime, a__EMEA: datetime, b__EMEA: datetime, region: str
) -> int:
   if region == "US":
       return (b__US - a__US).days
   if region == "EMEA":
       return (b__EMEA - a__EMEA).days
   raise ValueError("Region unknown.")

def ac_period(
   a__US: datetime,
   c__US: datetime,
   a__EMEA: datetime,
   c__EMEA: datetime,
   region: str,
) -> int:
   if region == "US":
       return (c__US - a__US).days
   if region == "EMEA":
       return (c__EMEA - a__EMEA).days
   raise ValueError("Region unknown.")

def bc_period(
   c__US: datetime, b__US: datetime, c__EMEA: datetime, b__EMEA: datetime, region: str
) -> int:
   if region == "US":
       return (c__US - b__US).days
   if region == "EMEA":
       return (c__EMEA - b__EMEA).days
   raise ValueError("Region unknown.")