diff --git a/serket/nn/fully_connected.py b/serket/nn/fully_connected.py
index 5fdf6a7..65a1c26 100644
--- a/serket/nn/fully_connected.py
+++ b/serket/nn/fully_connected.py
@@ -14,9 +14,10 @@
 
 from __future__ import annotations
 
-from typing import Any, Sequence
+from typing import Any, Generic, Sequence, TypeVar
 
 import jax
+import jax.numpy as jnp
 import jax.random as jr
 
 import serket as sk
@@ -28,6 +29,13 @@
 from serket.nn.initialization import InitType
 from serket.nn.linear import Linear
 
+T = TypeVar("T")
+
+
+class Batched(Generic[T]):
+    pass
+
+
 PyTree = Any
 
 
@@ -73,11 +81,8 @@ def __init__(
         num_hidden_layers = len(layers) - 2
 
         if isinstance(act_func, tuple):
-            if len(act_func) != (num_hidden_layers + 1):
-                raise ValueError(
-                    "tuple of activation functions must have "
-                    f"length: {(num_hidden_layers+1)=}, "
-                )
+            if len(act_func) != (num_hidden_layers):
+                raise ValueError(f"{len(act_func)=} != {(num_hidden_layers)=}")
 
             self.act_func = tuple(resolve_activation(act) for act in act_func)
         else:
@@ -224,11 +229,8 @@ def __init__(
         keys = jr.split(key, num_hidden_layers + 1)
 
         if isinstance(act_func, tuple):
-            if len(act_func) != (num_hidden_layers + 1):
-                raise ValueError(
-                    "tuple of activation functions must have "
-                    f"length: {(num_hidden_layers+1)=}, "
-                )
+            if len(act_func) != (num_hidden_layers):
+                raise ValueError(f"{len(act_func)=} != {(num_hidden_layers)=}")
             self.act_func = tuple(resolve_activation(act) for act in act_func)
         else:
             self.act_func = resolve_activation(act_func)
@@ -244,58 +246,6 @@ def batched_linear(key) -> Batched[Linear]:
             + [Linear(hidden_size, out_features, key=keys[-1], **kwargs)]
         )
 
-    def _single_call(self, x: jax.Array, **k) -> jax.Array:
-        x = self.act_func(self.in_layer(x))
-
-        if self.mid_layer.bias is None:
-
-            def scan_mid_layer(x: jax.Array, weight_bias: jax.Array):
-                weight, bias = weight_bias[..., :-1], weight_bias[..., -1]
-                return self.act_func(x @ weight + bias), None
-
-            x, _ = jax.lax.scan(scan_mid_layer, x, self.mid_layer.bias)
-
-        else:
-            bias = self.mid_layer.bias[:, :, None]
-            weight_bias = jnp.concatenate([self.mid_layer.weight, bias], axis=-1)
-
-            def scan_mid_layer(x: jax.Array, weight_bias: jax.Array):
-                weight, bias = weight_bias[..., :-1], weight_bias[..., -1]
-                return self.act_func(x @ weight + bias), None
-
-            x, _ = jax.lax.scan(scan_mid_layer, x, weight_bias)
-
-        x = self.out_layer(x)
-        return x
-
-    def _multi_call(self, x: jax.Array, **k) -> jax.Array:
-        a0, *ah = self.act_func
-        x = a0(self.in_layer(x))
-
-        if self.mid_layer.bias is None:
-
-            def scan_mid_layer(x_index: jax.Array, weight: jax.Array):
-                x, index = x_index
-                x = jax.lax.switch(index, ah, x @ weight)
-                return [x, index + 1], None
-
-            (x, _), _ = jax.lax.scan(scan_mid_layer, [x, 0], self.mid_layer.weight)
-
-        else:
-            bias = self.mid_layer.bias[:, :, None]
-            weight_bias = jnp.concatenate([self.mid_layer.weight, bias], axis=-1)
-
-            def scan_mid_layer(x_index: jax.Array, weight_bias: jax.Array):
-                x, index = x_index
-                weight, bias = weight_bias[..., :-1], weight_bias[..., -1]
-                x = jax.lax.switch(index, ah, x @ weight + bias)
-                return [x, index + 1], None
-
-            (x, _), _ = jax.lax.scan(scan_mid_layer, [x, 0], weight_bias)
-
-        x = self.out_layer(x)
-        return x
-
     def __call__(self, x: jax.Array, **k) -> jax.Array:
         l0, lm, lh = self.layers