diff --git a/src/customer_attributes.py b/src/customer_attributes.py
index 10929ce..fff9121 100644
--- a/src/customer_attributes.py
+++ b/src/customer_attributes.py
@@ -1,22 +1,25 @@
+from dataclasses import dataclass, field
 from typing import ClassVar
-from pydantic import BaseModel, model_validator
+
 from src.models import KeypadSize
 from src.utils import generate_random_nonrepeating_list
 
 
-class CustomerAttributes(BaseModel):
+@dataclass
+class CustomerAttributes:
     attr_vals: list[int]
     set_vals: list[int]
     keypad_size: KeypadSize
     MAX_KEYS: ClassVar[int] = 256
     MAX_ATTRS_PER_KEY: ClassVar[int] = 256
 
-    @model_validator(mode='after')
-    def check_keys_vs_attrs(self) -> 'CustomerAttributes':
+    def __post_init__(self):
+        self.check_keys_vs_attrs()
+
+    def check_keys_vs_attrs(self) -> None:
         if self.keypad_size.is_dispersable:
             raise ValueError("number of keys must be less than the number of "
                              "attributes per key to be dispersion resistant")
-        return self
 
     @classmethod
     def create(cls, keypad_size: KeypadSize) -> 'CustomerAttributes':
@@ -41,4 +44,4 @@ class CustomerAttributes(BaseModel):
     def get_set_index(self, set_val: int) -> int:
         if set_val not in self.set_vals:
             raise ValueError(f"Set value {set_val} not found in set values")
-        return self.set_vals.index(set_val)
+        return self.set_vals.index(set_val)
\ No newline at end of file