Allow datetime in limit parameters for logs_from.

Add time_snowflake to convert a datetime to a "snowflake".

discord/utils.py

@@ -106,6 +106,24 @@ def snowflake_time(id):
     """Returns the creation date in UTC of a discord id."""
     return datetime.datetime.utcfromtimestamp(((int(id) >> 22) + DISCORD_EPOCH) / 1000)
 
+def time_snowflake(datetime_obj, high=False):
+    """Returns a numeric snowflake pretending to be created at the given date.
+
+    When using as the lower end of a range, use time_snowflake(high=False) - 1 to be inclusive, high=True to be exclusive
+    When using as the higher end of a range, use time_snowflake(high=True) + 1 to be inclusive, high=False to be exclusive
+
+    Parameters
+    -----------
+    datetime_obj
+        A timezone-naive datetime object representing UTC time.
+    high
+        Whether or not to set the lower 22 bit to high or low.
+    """
+    unix_seconds = (datetime_obj - type(datetime_obj)(1970, 1, 1)).total_seconds()
+    discord_millis = int(unix_seconds * 1000 - DISCORD_EPOCH)
+
+    return (discord_millis << 22) + (2**22-1 if high else 0)
+
 def find(predicate, seq):
     """A helper to return the first element found in the sequence
     that meets the predicate. For example: ::