diff --git a/swh/search/utils.py b/swh/search/utils.py
index e29a2e5..464c435 100644
--- a/swh/search/utils.py
+++ b/swh/search/utils.py
@@ -1,111 +1,111 @@
 # Copyright (C) 2021  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import codecs
 from datetime import datetime
 from typing import Optional
 
-import iso8601  # type: ignore
+import iso8601
 
 
 def get_expansion(field, sep=None):
     METADATA_FIELDS = {
         "licenses": ["intrinsic_metadata", "http://schema.org/license", "@id"],
         "programming_languages": [
             "intrinsic_metadata",
             "http://schema.org/programmingLanguage",
             "@value",
         ],
         "keywords": ["intrinsic_metadata", "http://schema.org/keywords", "@value",],
         "descriptions": [
             "intrinsic_metadata",
             "http://schema.org/description",
             "@value",
         ],
         "date_created": [
             "intrinsic_metadata",
             "http://schema.org/dateCreated",
             "@value",
         ],
         "date_modified": [
             "intrinsic_metadata",
             "http://schema.org/dateModified",
             "@value",
         ],
         "date_published": [
             "intrinsic_metadata",
             "http://schema.org/datePublished",
             "@value",
         ],
     }
 
     if sep:
         return sep.join(METADATA_FIELDS[field])
 
     return METADATA_FIELDS[field]
 
 
 def parse_and_format_date(date_str: str) -> Optional[str]:
     """
     Parses a string date in the format %Y-%m-%d or ISO8601 and returns
     a new string date in the format YYYY-mm-dd if the parsing succeeded
     otherwise None.
     """
     try:
         return datetime.strptime(date_str, "%Y-%m-%d").strftime("%Y-%m-%d")
     except Exception:
         try:
             return iso8601.parse_date(date_str).strftime("%Y-%m-%d")
         except Exception:
             return None
 
 
 def escape(obj):
     r"""Makes the object directly injectable into the
     query language by converting the escapable parts of
     the object into escape sequences.
 
     For strings, appends \ before special characters like ', ", and \
 
     For arrays, applies the same transformation on each element, joins the
     elements and returns a string-like representation of the list.
 
     >>> print(escape("foo ' bar"))
     "foo \' bar"
 
     >>> print(escape([r"foo ' bar", r"bar \\\' baz", r'foo " baz']))
     ["foo \' bar", "bar \\\\\\\' baz", "foo \" baz"]
 
     """
     if type(obj) == list:
         items = [escape(item) for item in obj]
         return "[" + ", ".join(items) + "]"
     elif type(obj) == str:
         return (
             '"'
             + obj.translate({ord("'"): r"\'", ord('"'): r"\"", ord("\\"): r"\\",})
             + '"'
         )
     else:
         raise Exception(f"Unexpected item type {type(obj)}")
 
 
 def unescape(string):
     r"""Processes the escaped special characters
 
     >>> unescape(r'''foo " bar''') == r'''foo " bar'''
     True
     >>> unescape(r'''foo \" bar''') == r'''foo " bar'''
     True
     >>> unescape(r'''foo \\" bar''') == r'''foo \" bar'''
     True
     >>> unescape(r'''foo \\\" bar''') == r'''foo \" bar'''
     True
     >>> unescape(r'''foo \\\\" bar''') == r'''foo \\" bar'''
     True
     >>> unescape(r'''café \" foo''') == r'''café " foo'''
     True
     """
     return codecs.escape_decode(string.encode())[0].decode()