diff --git a/brainunit/math/_fun_keep_unit.py b/brainunit/math/_fun_keep_unit.py
index 277486e..87247f1 100644
--- a/brainunit/math/_fun_keep_unit.py
+++ b/brainunit/math/_fun_keep_unit.py
@@ -443,7 +443,7 @@ def _broadcast_fun(func, *args, **kwargs):
   args = [asarray(x) for x in args]
   args, treedef = jax.tree.flatten(args)
   r = func(*args, **kwargs)
-  r = treedef.unflatten(r)
+  r = treedef.unflatten([r] if isinstance(r, jax.Array) else r)
   if len(r) == 1:
     return r[0]
   return r
@@ -485,7 +485,7 @@ def atleast_1d(
 
   Parameters
   ----------
-  *args : array_like, Quantity
+  *arys : array_like, Quantity
     One or more input arrays or quantities.
 
   Returns
@@ -505,7 +505,7 @@ def atleast_2d(
 
   Parameters
   ----------
-  *args : array_like, Quantity
+  *arys : array_like, Quantity
     One or more input arrays or quantities.
 
   Returns
@@ -525,7 +525,7 @@ def atleast_3d(
 
   Parameters
   ----------
-  *args : array_like, Quantity
+  *arys : array_like, Quantity
     One or more input arrays or quantities.
 
   Returns