in src/mapillary/utils/filter.py [0:0]
def existed_before(data: list, existed_before: str) -> list:
"""
Whether the first_seen_at properly existed before a specified time period
:param data: The feature list
:type data: list
:param existed_before: The UNIX timestamp
:type existed_before: str
:return: A feature list
:rtype: list
"""
return [
feature
for feature in data
if feature["properties"]["first_seen_at"]
<= date_to_unix_timestamp(existed_before)
]