diff --git a/pyproject.toml b/pyproject.toml
index 2cfaf4c..521467a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -36,14 +36,16 @@ src = ["src"]    # consider folder as first-party import
 
 [tool.ruff.lint]
 extend-select = [
-    "B",   # flake8-bugbear
-    "I",   # isort
-    "N",   # pep8 naming
-    "SIM", # flake8-simplify, for simplified code
-    "PTH", # pathlib (instead of os.path)
-    "W",   # warning
-    "T2",  # flake8-print (avoiding prints)
-    "S",   # bandit, security checks
+    "B",    # flake8-bugbear
+    "D212", # docstring first line should end with period
+    "D415", # multiline docstring should start at first line
+    "I",    # isort
+    "N",    # pep8 naming
+    "PTH",  # pathlib (instead of os.path)
+    "S",    # bandit, security checks
+    "SIM",  # flake8-simplify, for simplified code
+    "T2",   # flake8-print (avoiding prints)
+    "W",    # warning
 ]
 ignore = [
     "N818",   # error suffix in exception names
@@ -52,6 +54,8 @@ ignore = [
 ]
 
 [tool.ruff.lint.per-file-ignores]
-"**/tests/*" = ["T"]
+"**/tests/*" = [
+    "S101", # Use of `assert` detected
+    "T",    # flake8-print (avoiding prints)
+]
 "examples/*" = ["T"]
-"**/tests*" = ["S101"] # Use of `assert` detected
diff --git a/src/mijnbib/login_handlers.py b/src/mijnbib/login_handlers.py
index 763bef1..c867a12 100644
--- a/src/mijnbib/login_handlers.py
+++ b/src/mijnbib/login_handlers.py
@@ -32,7 +32,7 @@ def login(self) -> mechanize.Browser:
 
 
 class LoginByForm(LoginHandler):
-    """Uses mechanize library to log in"""
+    """Uses mechanize library to log in."""
 
     def login(self) -> mechanize.Browser:
         response = self._log_in()
@@ -132,7 +132,7 @@ def _log_in(self):
 
 
 def _validate_logged_in(html: str) -> None:
-    """Raises AuthenticationError if login failed."""
+    """Raise AuthenticationError if login failed."""
     _log.debug("Checking if login is successful ...")
     if "Profiel" not in html:
         if (
diff --git a/src/mijnbib/mijnbibliotheek.py b/src/mijnbib/mijnbibliotheek.py
index 4a37ce9..fd29d54 100644
--- a/src/mijnbib/mijnbibliotheek.py
+++ b/src/mijnbib/mijnbibliotheek.py
@@ -1,5 +1,5 @@
-"""
-Webscraper module for interacting with the mijn.bibliotheek.be website.
+"""Webscraper module for interacting with the mijn.bibliotheek.be website.
+
 Created (initial version) on July 14, 2015
 
 For usage of this module, see the examples folder and the docstrings
@@ -168,12 +168,12 @@ def get_accounts(self) -> list[Account]:
         return accounts
 
     def get_all_info(self, all_as_dicts=False) -> dict:
-        """Returns all available information, for all accounts.
+        """Return all available information, for all accounts.
 
         Information is returned as a dict, with account ids as keys.
 
         Args:
-            all_as_dicts    When True, do not return dataclass objects, but dicts
+            all_as_dicts:   When True, do not return dataclass objects, but dicts
                             instead.
         Raises:
             AuthenticationError
diff --git a/src/mijnbib/parsers.py b/src/mijnbib/parsers.py
index 203e4f7..0c8ecae 100644
--- a/src/mijnbib/parsers.py
+++ b/src/mijnbib/parsers.py
@@ -38,7 +38,7 @@ def __init__(self, html: str, base_url: str, account_id: str):
         self._acc_id = account_id
 
     def parse(self) -> list[Loan]:
-        """Return loans
+        """Return loans.
 
         >>> html_string='''
         ... <div class="my-library-user-library-account-loans__loan-wrapper">
@@ -138,7 +138,7 @@ def parse(self) -> list[Loan]:
         return loans
 
     def _get_loan_info_from_div(self, loan_div_html: str, branch: str) -> Loan:
-        """Return loan from html loan_div blob"""
+        """Return loan from html loan_div blob."""
         loan_div = BeautifulSoup(loan_div_html, "html.parser")
         loan = {}
 
@@ -229,7 +229,7 @@ def __init__(self, html: str, base_url: str):
         self._base_url = base_url
 
     def parse(self) -> list[Account]:
-        """Return list of accounts
+        """Return list of accounts.
 
         >>> html_string = '''
         ... ...
@@ -376,7 +376,7 @@ def parse(self) -> list[Account]:
 
     @staticmethod
     def _parse_item_count_from_li(acc_div, class_: str) -> int | None:
-        """Return None if no info found, otherwise return item count (potentially 0)"""
+        """Return None if no info found, otherwise return item count (potentially 0)."""
         item_count = None
         try:
             acc_a_text = acc_div.find("li", class_=class_).a.get_text().strip()
@@ -396,7 +396,7 @@ def __init__(self, html: str):
         self._html = html
 
     def parse(self) -> list[Reservation]:
-        """Return list of holds
+        """Return list of holds.
 
         >>> html_string='''
         ... <div class="my-library-user-library-account-holds__hold-wrapper">
@@ -544,20 +544,20 @@ def __init__(self, html: str):
         self._html = html
 
     def parse(self) -> dict:
-        """For dict structure, see the called method"""
+        """For dict structure, see the called method."""
         html_blob = self._extract_html_from_response_script_tag()
         return self._parse_extend_response_status_blob(html_blob)
 
     def _extract_html_from_response_script_tag(self):
-        """
+        """Return html-encoded data from ajax encoded data.
+
         The extending loan response contains the result in a ajax script thingy.
         This function extracts the part we are interested in and returns the decoded html.
-
         See the tests for an example.
         """
 
         def find_between(s: str, start: str, end: str):
-            """find_between("aabbcc", "aa", "cc") returns "bb" """
+            # find_between("aabbcc", "aa", "cc") returns "bb"
             return s[s.find(start) + len(start) : s.rfind(end)]
 
         # find relevant snippet
@@ -575,7 +575,7 @@ def find_between(s: str, start: str, end: str):
 
     @classmethod
     def _parse_extend_response_status_blob(cls, html_string: str) -> dict:
-        """Return details on loans that where extended succesfully
+        """Return details on loans that where extended succesfully.
 
         >>> html_string = '''
         ... <div role="contentinfo" aria-label="Statusbericht" class="messages messages--status"