diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 4a03eac..dafcbf6 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -33,7 +33,7 @@ repos:
           - flake8-print
 # Using this mirror lets us use mypyc-compiled black, which is about 2x faster
 - repo: https://github.com/psf/black-pre-commit-mirror
-  rev: 25.12.0
+  rev: 26.1.0
   hooks:
     - id: black
 - repo: https://github.com/pre-commit/pygrep-hooks
diff --git a/changethelog.py b/changethelog.py
index be9ded1..6c176cb 100644
--- a/changethelog.py
+++ b/changethelog.py
@@ -1,5 +1,6 @@
 #!/usr/bin/python
 """Automatically update changelog."""
+
 import sys
 from datetime import datetime
 
diff --git a/src/hmf/mass_function/fitting_functions.py b/src/hmf/mass_function/fitting_functions.py
index 6b260f8..36bf4d7 100644
--- a/src/hmf/mass_function/fitting_functions.py
+++ b/src/hmf/mass_function/fitting_functions.py
@@ -117,21 +117,19 @@ def _makedoc(pdocs, lname, sname, eq, ref):
     %s mass function fit.
 
     For details on attributes, see documentation for :class:`FittingFunction`.
-    """
-        % lname
+    """ % lname
         + pdocs
         + r"""
     Notes
     -----
-    The %s [1]_ form is:
+    The {} [1]_ form is:
 
-    .. math:: f_{\rm %s}(\sigma) = %s
+    .. math:: f_{{\rm {}}}(\sigma) = {}
 
     References
     ----------
-    .. [1] %s
-    """
-        % (lname, sname, eq, ref)
+    .. [1] {}
+    """.format(lname, sname, eq, ref)
     )