diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 3d2fbf502..ed258a08f 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -8,7 +8,7 @@ repos:
       - id: isort
 
   - repo: https://github.com/psf/black
-    rev: 22.1.0
+    rev: 22.3.0
     hooks:
       - id: black
 
diff --git a/src/betterproto/__init__.py b/src/betterproto/__init__.py
index e6af1bcb8..2faa12236 100644
--- a/src/betterproto/__init__.py
+++ b/src/betterproto/__init__.py
@@ -433,7 +433,7 @@ def _parse_float(value: Any) -> float:
 
     Parameters
     ----------
-    value : Any
+    value: Any
         Value to parse
 
     Returns
@@ -455,20 +455,19 @@ def _dump_float(value: float) -> Union[float, str]:
 
     Parameters
     ----------
-    value : float
+    value: float
         Value to dump
 
     Returns
     -------
     Union[float, str]
-        Dumped valid, either a float or the strings
-        "Infinity" or "-Infinity"
+        Dumped value, either a float or the strings
     """
     if value == float("inf"):
         return INFINITY
     if value == -float("inf"):
         return NEG_INFINITY
-    if value == float("nan"):
+    if isinstance(value, float) and math.isnan(value):
         return NAN
     return value