my.instagram: add initial all.py + some experiments on nicer errors

my/instagram/common.py

@@ -0,0 +1,30 @@
+from datetime import datetime
+from itertools import chain
+from typing import Iterator
+
+from my.core import warn_if_empty, Res
+from my.core.compat import Protocol
+
+from more_itertools import unique_everseen
+
+
+class Message(Protocol):
+    created: datetime
+    text: str
+    # TODO add some sort of thread id
+
+
+@warn_if_empty
+def _merge_messages(*sources: Iterator[Res[Message]]) -> Iterator[Res[Message]]:
+    def key(r: Res[Message]):
+        if isinstance(r, Exception):
+            # NOTE: using str() against Exception is nice so exceptions with same args are treated the same..
+            return str(r)
+
+        dt = r.created
+        # seems that GDPR has millisecond resolution.. so best to strip them off when merging
+        round_us = dt.microsecond // 1000 * 1000
+        without_us = r.created.replace(microsecond=round_us)
+        # using text as key is a bit crap.. but atm there are no better shared fields
+        return (without_us, r.text)
+    return unique_everseen(chain(*sources), key=key)