diff --git a/cf/data/data.py b/cf/data/data.py
index f9c2d3bb50..2ba56705d7 100644
--- a/cf/data/data.py
+++ b/cf/data/data.py
@@ -9105,25 +9105,16 @@ def dump(self, display=True, prefix=None):
         if prefix is None:
             prefix = self.__class__.__name__
 
-        string = ["{0}.shape = {1}".format(prefix, self._shape)]
+        string = [f"{prefix}.shape = {self.shape}"]
 
-        if self._size == 1:
-            string.append(
-                "{0}.first_datum = {1}".format(prefix, self.datum(0))
-            )
+        if self.size == 1:
+            string.append(f"{prefix}.first_datum = {self.datum(0)}")
         else:
-            string.append(
-                "{0}.first_datum = {1}".format(prefix, self.datum(0))
-            )
-            string.append(
-                "{0}.last_datum  = {1}".format(prefix, self.datum(-1))
-            )
+            string.append(f"{prefix}.first_datum = {self.datum(0)}")
+            string.append(f"{prefix}.last_datum  = {self.datum(-1)}")
 
         for attr in ("fill_value", "Units"):
-            string.append(
-                "{0}.{1} = {2!r}".format(prefix, attr, getattr(self, attr))
-            )
-        # --- End: for
+            string.append(f"{prefix}.{attr} = {getattr(self, attr)!r}")
 
         return "\n".join(string)
 
diff --git a/cf/functions.py b/cf/functions.py
index ebb12c20fa..4c8355a38f 100644
--- a/cf/functions.py
+++ b/cf/functions.py
@@ -13,7 +13,6 @@
 from collections.abc import Iterable
 from itertools import product
 from marshal import dumps
-from math import ceil as math_ceil
 from numbers import Integral
 from os import getpid, listdir, mkdir
 from os.path import abspath as _os_path_abspath
@@ -25,9 +24,9 @@
 
 import cfdm
 import netCDF4
+import numpy as np
 from dask import config
 from dask.utils import parse_bytes
-import numpy as np
 from numpy import __file__ as _numpy__file__
 from numpy import __version__ as _numpy__version__
 from numpy import all as _numpy_all
diff --git a/cf/test/test_Data.py b/cf/test/test_Data.py
index 9e6a610ab8..31e603279a 100644
--- a/cf/test/test_Data.py
+++ b/cf/test/test_Data.py
@@ -3938,6 +3938,14 @@ def test_Data_tolist(self):
             self.assertEqual(e, np.array(x).tolist())
             self.assertTrue(d.equals(cf.Data(e)))
 
+    def test_Data_dump(self):
+        d = cf.Data([1, 2], "m")
+        x = (
+            "Data.shape = (2,)\nData.first_datum = 1\nData.last_datum  = 2\n"
+            "Data.fill_value = None\nData.Units = <Units: m>"
+        )
+        self.assertEqual(d.dump(display=False), x)
+
 
 if __name__ == "__main__":
     print("Run date:", datetime.datetime.now())