tz -> zone, update iter_tzs depends on, misc changes

doc/MODULES.org

@@ -160,7 +160,7 @@ For an extensive/complex example, you can check out ~@seanbreckenridge~'s [[http
     - you might trust your original timezone, or it might just be UTC, and you want to use something more reasonable
 
    #+begin_src python
-   Policy = Literal[
+   TzPolicy = Literal[
        'keep'   , # if datetime is tz aware, just preserve it
        'convert', # if datetime is tz aware, convert to provider's tz
        'throw'  , # if datetime is tz aware, throw exception

my/ip/all.py

@@ -11,11 +11,12 @@ REQUIRES = ["git+https://github.com/seanbreckenridge/ipgeocache"]
 
 from typing import Iterator
 
-from my.core.common import Stats
+from my.core.common import Stats, warn_if_empty
 
 from .common import IP
 
 
+@warn_if_empty
 def ips() -> Iterator[IP]:
     yield from ()
 

my/ip/common.py

@@ -24,7 +24,7 @@ class IP(NamedTuple):
         return ipgeocache.get(self.addr)
 
     @property
-    def tz(self) -> str:
+    def tzname(self) -> str:
         tz: str = self.ipgeocache()["timezone"]
         return tz
 

my/location/common.py

@@ -10,8 +10,8 @@ LatLon = Tuple[float, float]
 
 # TODO: add timezone to this? can use timezonefinder in tz provider instead though
 class Location(NamedTuple):
-    lon: float
     lat: float
+    lon: float
     dt: datetime
     accuracy: Optional[float]
     elevation: Optional[float]

my/time/tz/via_location.py

@@ -106,8 +106,23 @@ def most_common(lst: List[DayWithZone]) -> DayWithZone:
     return res
 
 
-# refresh _iter_tzs once per day -- don't think a better depends_on is possible dynamically
-@mcachew(logger=logger, depends_on=lambda: str(date.today()))
+def _iter_tz_depends_on() -> str:
+    """
+    Since you might get new data which specifies a new timezone sometime
+    in the day, this causes _iter_tzs to refresh every 6 hours, like:
+    2022-04-26_00
+    2022-04-26_06
+    2022-04-26_12
+    2022-04-26_18
+    """
+    day = str(date.today())
+    hr = datetime.now().hour
+    hr_truncated = hr // 6 * 6
+    return "{}_{}".format(day, hr_truncated)
+
+
+# refresh _iter_tzs every 6 hours -- don't think a better depends_on is possible dynamically
+@mcachew(logger=logger, depends_on=_iter_tz_depends_on)
 def _iter_tzs() -> Iterator[DayWithZone]:
     # since we have no control over what order the locations are returned,
     # we need to sort them first before we can do a groupby