diff --git a/requirements.txt b/requirements.txt
index 4f3f588..3ad87c4 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,7 @@
 SQLAlchemy
 arrow
 python_debian
 requests
 setuptools
 xmltodict
+iso8601
diff --git a/swh/lister/bitbucket/lister.py b/swh/lister/bitbucket/lister.py
index 8da6d22..ae5866c 100644
--- a/swh/lister/bitbucket/lister.py
+++ b/swh/lister/bitbucket/lister.py
@@ -1,40 +1,71 @@
 # Copyright (C) 2017-2018 the Software Heritage developers
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 from urllib import parse
+import logging
+import iso8601
 
 from swh.lister.bitbucket.models import BitBucketModel
 from swh.lister.core.indexing_lister import SWHIndexingHttpLister
 
 
+logger = logging.getLogger(__name__)
+
+
 class BitBucketLister(SWHIndexingHttpLister):
     PATH_TEMPLATE = '/repositories?after=%s'
     MODEL = BitBucketModel
     LISTER_NAME = 'bitbucket'
 
     def get_model_from_repo(self, repo):
         return {
             'uid': repo['uuid'],
             'indexable': repo['created_on'],
             'name': repo['name'],
             'full_name': repo['full_name'],
             'html_url': repo['links']['html']['href'],
             'origin_url': repo['links']['clone'][0]['href'],
             'origin_type': repo['scm'],
             'description': repo['description']
         }
 
     def get_next_target_from_response(self, response):
         body = response.json()
         if 'next' in body:
             return parse.unquote(body['next'].split('after=')[1])
         else:
             return None
 
     def transport_response_simplified(self, response):
         repos = response.json()['values']
         return [self.get_model_from_repo(repo) for repo in repos]
 
     def request_uri(self, identifier):
         return super().request_uri(identifier or '1970-01-01')
+
+    def is_within_bounds(self, inner, lower=None, upper=None):
+        # values are expected to be str dates
+        try:
+            inner = iso8601.parse_date(inner)
+            if lower:
+                lower = iso8601.parse_date(lower)
+            if upper:
+                upper = iso8601.parse_date(upper)
+            if lower is None and upper is None:
+                return True
+            elif lower is None:
+                ret = inner <= upper
+            elif upper is None:
+                ret = inner >= lower
+            else:
+                ret = lower <= inner <= upper
+        except Exception as e:
+            logger.error(str(e) + ': %s, %s, %s' %
+                         (('inner=%s%s' % (type(inner), inner)),
+                          ('lower=%s%s' % (type(lower), lower)),
+                          ('upper=%s%s' % (type(upper), upper)))
+                         )
+            raise
+
+        return ret
diff --git a/swh/lister/bitbucket/tests/test_bb_lister.py b/swh/lister/bitbucket/tests/test_bb_lister.py
index 7769e00..3db69dc 100644
--- a/swh/lister/bitbucket/tests/test_bb_lister.py
+++ b/swh/lister/bitbucket/tests/test_bb_lister.py
@@ -1,20 +1,29 @@
 # Copyright (C) 2017-2018 the Software Heritage developers
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import re
 import unittest
 
 from swh.lister.bitbucket.lister import BitBucketLister
 from swh.lister.core.tests.test_lister import HttpListerTester
 
 
 class BitBucketListerTester(HttpListerTester, unittest.TestCase):
     Lister = BitBucketLister
     test_re = re.compile(r'/repositories\?after=([^?&]+)')
     lister_subdir = 'bitbucket'
     good_api_response_file = 'api_response.json'
     bad_api_response_file = 'api_empty_response.json'
     first_index = '2008-07-12T07:44:01.476818+00:00'
     last_index = '2008-07-19T06:16:43.044743+00:00'
     entries_per_page = 10
+
+    def test_is_within_bounds(self):
+        fl = self.get_fl()
+        self.assertTrue(fl.is_within_bounds(
+            '2008-07-15', self.first_index, self.last_index))
+        self.assertFalse(fl.is_within_bounds(
+            '2008-07-20', self.first_index, self.last_index))
+        self.assertFalse(fl.is_within_bounds(
+            '2008-07-11', self.first_index, self.last_index))