diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 28dfdd0dfc..b8632cdd54 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -9,7 +9,7 @@ repos:
       - id: check-yaml
       - id: debug-statements
   - repo: https://github.com/psf/black
-    rev: 24.1.1
+    rev: 24.2.0
     hooks:
       - id: black
   - repo: https://github.com/pycqa/isort
diff --git a/src/qibo/quantum_info/random_ensembles.py b/src/qibo/quantum_info/random_ensembles.py
index b1be867620..94159cf1b2 100644
--- a/src/qibo/quantum_info/random_ensembles.py
+++ b/src/qibo/quantum_info/random_ensembles.py
@@ -32,10 +32,10 @@ def _ppf(self, theta: float):
 
 
 def uniform_sampling_U3(ngates: int, seed=None, backend=None):
-    """Samples parameters for Haar-random :math:`U_{3}`s (:class:`qibo.gates.U3`).
+    """Samples parameters for Haar-random :class:`qibo.gates.U3`.
 
     Args:
-        ngates (int): Total number of :math:`U_{3}`s to be sampled.
+        ngates (int): Total number of :math:`U_{3}` gates to be sampled.
         seed (int or :class:`numpy.random.Generator`, optional): Either a generator of random
             numbers or a fixed seed to initialize a generator. If ``None``, initializes
             a generator with a random seed. Default: ``None``.
@@ -44,7 +44,7 @@ def uniform_sampling_U3(ngates: int, seed=None, backend=None):
             Defaults to ``None``.
 
     Returns:
-        (ndarray): array of shape (``ngates``, :math:`3`).
+        ndarray: array of shape (``ngates``, :math:`3`).
     """
     if not isinstance(ngates, int):
         raise_error(