Expected
nowtime:2026-01-08 21:38:10
"yesterday +1h" parse into: 2026-01-07 22:38:10
"yesterday -1h" parse into: 2026-01-07 20:38:10

Actually
nowtime:2026-01-08 21:38:10
"yesterday +1h" parse into: 2026-01-07 20:38:10
"yesterday -1h" parse into: 2026-01-07 20:38:10

since "yesterday +1h" and "yesterday -1h" parse into same thing,there must be some problem.

TestCode

from dateparser import parse

test_dates = [
    "yesterday +1h",
    "yesterday -1h"
]

for d in test_dates:
    result = parse(d)
    print(f"Input: {d} -> Parsed: {result}")