diff --git a/alembic/env.py b/alembic/env.py
index 1340432..63515a4 100644
--- a/alembic/env.py
+++ b/alembic/env.py
@@ -4,6 +4,7 @@ from sqlalchemy import engine_from_config
 from sqlalchemy import pool
 
 from alembic import context
+from app.db.base import Base
 
 # this is the Alembic Config object, which provides
 # access to the values within the .ini file in use.
@@ -16,7 +17,6 @@ if config.config_file_name is not None:
 
 # add your model's MetaData object here
 # for 'autogenerate' support
-from app.db.base import Base
 target_metadata = Base.metadata
 
 # other values from the config, defined by the needs of env.py,
@@ -63,9 +63,7 @@ def run_migrations_online() -> None:
     )
 
     with connectable.connect() as connection:
-        context.configure(
-            connection=connection, target_metadata=target_metadata
-        )
+        context.configure(connection=connection, target_metadata=target_metadata)
 
         with context.begin_transaction():
             context.run_migrations()
@@ -74,4 +72,4 @@ def run_migrations_online() -> None:
 if context.is_offline_mode():
     run_migrations_offline()
 else:
-    run_migrations_online()
\ No newline at end of file
+    run_migrations_online()
diff --git a/alembic/versions/001_initial_setup.py b/alembic/versions/001_initial_setup.py
index 50fb018..b5ce5d1 100644
--- a/alembic/versions/001_initial_setup.py
+++ b/alembic/versions/001_initial_setup.py
@@ -1,16 +1,17 @@
 """initial setup
 
 Revision ID: 001
-Revises: 
+Revises:
 Create Date: 2025-05-13
 
 """
+
 from alembic import op
 import sqlalchemy as sa
 
 
 # revision identifiers, used by Alembic.
-revision = '001'
+revision = "001"
 down_revision = None
 branch_labels = None
 depends_on = None
@@ -19,20 +20,27 @@ depends_on = None
 def upgrade() -> None:
     # Create calculation table
     op.create_table(
-        'calculation',
-        sa.Column('id', sa.Integer(), nullable=False),
-        sa.Column('operation', sa.String(), nullable=False),
-        sa.Column('first_number', sa.Float(), nullable=False),
-        sa.Column('second_number', sa.Float(), nullable=True),
-        sa.Column('result', sa.Float(), nullable=False),
-        sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('CURRENT_TIMESTAMP'), nullable=False),
-        sa.PrimaryKeyConstraint('id')
+        "calculation",
+        sa.Column("id", sa.Integer(), nullable=False),
+        sa.Column("operation", sa.String(), nullable=False),
+        sa.Column("first_number", sa.Float(), nullable=False),
+        sa.Column("second_number", sa.Float(), nullable=True),
+        sa.Column("result", sa.Float(), nullable=False),
+        sa.Column(
+            "created_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.text("CURRENT_TIMESTAMP"),
+            nullable=False,
+        ),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(op.f("ix_calculation_id"), "calculation", ["id"], unique=False)
+    op.create_index(
+        op.f("ix_calculation_operation"), "calculation", ["operation"], unique=False
     )
-    op.create_index(op.f('ix_calculation_id'), 'calculation', ['id'], unique=False)
-    op.create_index(op.f('ix_calculation_operation'), 'calculation', ['operation'], unique=False)
 
 
 def downgrade() -> None:
-    op.drop_index(op.f('ix_calculation_operation'), table_name='calculation')
-    op.drop_index(op.f('ix_calculation_id'), table_name='calculation')
-    op.drop_table('calculation')
\ No newline at end of file
+    op.drop_index(op.f("ix_calculation_operation"), table_name="calculation")
+    op.drop_index(op.f("ix_calculation_id"), table_name="calculation")
+    op.drop_table("calculation")
diff --git a/app/api/endpoints/calculator.py b/app/api/endpoints/calculator.py
index f29be9c..0d1c591 100644
--- a/app/api/endpoints/calculator.py
+++ b/app/api/endpoints/calculator.py
@@ -9,46 +9,59 @@ from app.crud import calculation
 
 router = APIRouter()
 
+
 def perform_calculation(calc: CalculationCreate) -> float:
     """Perform the calculation based on the operation and numbers provided."""
     if calc.operation == "add":
         if calc.second_number is None:
-            raise HTTPException(status_code=400, detail="Second number is required for addition")
+            raise HTTPException(
+                status_code=400, detail="Second number is required for addition"
+            )
         return calc.first_number + calc.second_number
-    
+
     elif calc.operation == "subtract":
         if calc.second_number is None:
-            raise HTTPException(status_code=400, detail="Second number is required for subtraction")
+            raise HTTPException(
+                status_code=400, detail="Second number is required for subtraction"
+            )
         return calc.first_number - calc.second_number
-    
+
     elif calc.operation == "multiply":
         if calc.second_number is None:
-            raise HTTPException(status_code=400, detail="Second number is required for multiplication")
+            raise HTTPException(
+                status_code=400, detail="Second number is required for multiplication"
+            )
         return calc.first_number * calc.second_number
-    
+
     elif calc.operation == "divide":
         if calc.second_number is None:
-            raise HTTPException(status_code=400, detail="Second number is required for division")
+            raise HTTPException(
+                status_code=400, detail="Second number is required for division"
+            )
         if calc.second_number == 0:
             raise HTTPException(status_code=400, detail="Cannot divide by zero")
         return calc.first_number / calc.second_number
-    
+
     elif calc.operation == "square_root":
         if calc.first_number < 0:
-            raise HTTPException(status_code=400, detail="Cannot calculate square root of a negative number")
+            raise HTTPException(
+                status_code=400,
+                detail="Cannot calculate square root of a negative number",
+            )
         return math.sqrt(calc.first_number)
-    
+
     else:
         raise HTTPException(
-            status_code=400, 
-            detail="Invalid operation. Supported operations: add, subtract, multiply, divide, square_root"
+            status_code=400,
+            detail="Invalid operation. Supported operations: add, subtract, multiply, divide, square_root",
         )
 
+
 @router.post("/", response_model=CalculationResponse)
 def calculate(calc: CalculationCreate, db: Session = Depends(get_db)):
     """
     Perform a calculation and store it in the database.
-    
+
     - **operation**: add, subtract, multiply, divide, or square_root
     - **first_number**: First operand
     - **second_number**: Second operand (not required for square_root)
@@ -57,14 +70,18 @@ def calculate(calc: CalculationCreate, db: Session = Depends(get_db)):
     db_calc = calculation.create_calculation(db=db, calc=calc, result=result)
     return db_calc
 
+
 @router.get("/history", response_model=List[CalculationResponse])
-def get_calculation_history(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
+def get_calculation_history(
+    skip: int = 0, limit: int = 100, db: Session = Depends(get_db)
+):
     """
     Retrieve calculation history.
     """
     calcs = calculation.get_calculations(db, skip=skip, limit=limit)
     return calcs
 
+
 @router.get("/{calculation_id}", response_model=CalculationResponse)
 def get_calculation_by_id(calculation_id: int, db: Session = Depends(get_db)):
     """
@@ -73,4 +90,4 @@ def get_calculation_by_id(calculation_id: int, db: Session = Depends(get_db)):
     db_calc = calculation.get_calculation(db, calculation_id=calculation_id)
     if db_calc is None:
         raise HTTPException(status_code=404, detail="Calculation not found")
-    return db_calc
\ No newline at end of file
+    return db_calc
diff --git a/app/api/endpoints/health.py b/app/api/endpoints/health.py
index 652d8a7..8eac7f4 100644
--- a/app/api/endpoints/health.py
+++ b/app/api/endpoints/health.py
@@ -4,6 +4,7 @@ from app.db.session import get_db
 
 router = APIRouter()
 
+
 @router.get("/health")
 def health_check(db: Session = Depends(get_db)):
     """
@@ -17,9 +18,5 @@ def health_check(db: Session = Depends(get_db)):
         db_status = "healthy"
     except Exception as e:
         db_status = f"unhealthy: {str(e)}"
-    
-    return {
-        "status": "healthy",
-        "database": db_status,
-        "version": "1.0.0"
-    }
\ No newline at end of file
+
+    return {"status": "healthy", "database": db_status, "version": "1.0.0"}
diff --git a/app/api/router.py b/app/api/router.py
index f15a21b..7878a08 100644
--- a/app/api/router.py
+++ b/app/api/router.py
@@ -3,4 +3,4 @@ from app.api.endpoints import calculator, health
 
 router = APIRouter()
 router.include_router(calculator.router, prefix="/calculator", tags=["calculator"])
-router.include_router(health.router, tags=["health"])
\ No newline at end of file
+router.include_router(health.router, tags=["health"])
diff --git a/app/core/config.py b/app/core/config.py
index 8657087..8657a93 100644
--- a/app/core/config.py
+++ b/app/core/config.py
@@ -1,17 +1,19 @@
 from pathlib import Path
 from pydantic_settings import BaseSettings
 
+
 class Settings(BaseSettings):
     API_V1_STR: str = "/api/v1"
     PROJECT_NAME: str = "Calculator API"
-    
+
     # Database settings
     DB_DIR = Path("/app") / "storage" / "db"
     DB_DIR.mkdir(parents=True, exist_ok=True)
     DATABASE_URL: str = f"sqlite:///{DB_DIR}/db.sqlite"
-    
+
     class Config:
         env_file = ".env"
         case_sensitive = True
 
-settings = Settings()
\ No newline at end of file
+
+settings = Settings()
diff --git a/app/crud/calculation.py b/app/crud/calculation.py
index 3ae4ef7..a6f5f6e 100644
--- a/app/crud/calculation.py
+++ b/app/crud/calculation.py
@@ -2,20 +2,31 @@ from sqlalchemy.orm import Session
 from app.models.calculation import Calculation
 from app.schemas.calculation import CalculationCreate
 
-def create_calculation(db: Session, calc: CalculationCreate, result: float) -> Calculation:
+
+def create_calculation(
+    db: Session, calc: CalculationCreate, result: float
+) -> Calculation:
     db_calculation = Calculation(
         operation=calc.operation,
         first_number=calc.first_number,
         second_number=calc.second_number,
-        result=result
+        result=result,
     )
     db.add(db_calculation)
     db.commit()
     db.refresh(db_calculation)
     return db_calculation
 
+
 def get_calculations(db: Session, skip: int = 0, limit: int = 100):
-    return db.query(Calculation).order_by(Calculation.created_at.desc()).offset(skip).limit(limit).all()
+    return (
+        db.query(Calculation)
+        .order_by(Calculation.created_at.desc())
+        .offset(skip)
+        .limit(limit)
+        .all()
+    )
+
 
 def get_calculation(db: Session, calculation_id: int):
-    return db.query(Calculation).filter(Calculation.id == calculation_id).first()
\ No newline at end of file
+    return db.query(Calculation).filter(Calculation.id == calculation_id).first()
diff --git a/app/db/base.py b/app/db/base.py
index 799f08a..e69de29 100644
--- a/app/db/base.py
+++ b/app/db/base.py
@@ -1,2 +0,0 @@
-from app.db.base_class import Base
-from app.models.calculation import Calculation
\ No newline at end of file
diff --git a/app/db/base_class.py b/app/db/base_class.py
index f4d43d6..b6e3745 100644
--- a/app/db/base_class.py
+++ b/app/db/base_class.py
@@ -1,11 +1,12 @@
 from typing import Any
 from sqlalchemy.ext.declarative import as_declarative, declared_attr
 
+
 @as_declarative()
 class Base:
     id: Any
     __name__: str
-    
+
     @declared_attr
     def __tablename__(cls) -> str:
-        return cls.__name__.lower()
\ No newline at end of file
+        return cls.__name__.lower()
diff --git a/app/db/session.py b/app/db/session.py
index ab0db0b..e514fae 100644
--- a/app/db/session.py
+++ b/app/db/session.py
@@ -9,14 +9,14 @@ DB_DIR.mkdir(parents=True, exist_ok=True)
 SQLALCHEMY_DATABASE_URL = f"sqlite:///{DB_DIR}/db.sqlite"
 
 engine = create_engine(
-    SQLALCHEMY_DATABASE_URL,
-    connect_args={"check_same_thread": False}
+    SQLALCHEMY_DATABASE_URL, connect_args={"check_same_thread": False}
 )
 SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
 
+
 def get_db():
     db = SessionLocal()
     try:
         yield db
     finally:
-        db.close()
\ No newline at end of file
+        db.close()
diff --git a/app/models/calculation.py b/app/models/calculation.py
index e21c19c..90389f2 100644
--- a/app/models/calculation.py
+++ b/app/models/calculation.py
@@ -2,10 +2,11 @@ from sqlalchemy import Column, Integer, String, Float, DateTime
 from sqlalchemy.sql import func
 from app.db.base_class import Base
 
+
 class Calculation(Base):
     id = Column(Integer, primary_key=True, index=True)
     operation = Column(String, index=True)
     first_number = Column(Float)
     second_number = Column(Float, nullable=True)
     result = Column(Float)
-    created_at = Column(DateTime(timezone=True), server_default=func.now())
\ No newline at end of file
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
diff --git a/app/schemas/calculation.py b/app/schemas/calculation.py
index 35ac1db..3ef2551 100644
--- a/app/schemas/calculation.py
+++ b/app/schemas/calculation.py
@@ -1,19 +1,26 @@
 from datetime import datetime
 from typing import Optional
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, Field, ConfigDict
+
 
 class CalculationBase(BaseModel):
-    operation: str = Field(..., description="Mathematical operation: add, subtract, multiply, divide, or square_root")
+    operation: str = Field(
+        ...,
+        description="Mathematical operation: add, subtract, multiply, divide, or square_root",
+    )
     first_number: float = Field(..., description="First operand")
-    second_number: Optional[float] = Field(None, description="Second operand (not required for square_root)")
+    second_number: Optional[float] = Field(
+        None, description="Second operand (not required for square_root)"
+    )
+
 
 class CalculationCreate(CalculationBase):
     pass
 
+
 class CalculationResponse(CalculationBase):
     id: int
     result: float
     created_at: datetime
 
-    class Config:
-        orm_mode = True
\ No newline at end of file
+    model_config = ConfigDict(from_attributes=True)
diff --git a/main.py b/main.py
index 255708b..820b0de 100644
--- a/main.py
+++ b/main.py
@@ -11,4 +11,4 @@ app = FastAPI(
 app.include_router(api_router, prefix=settings.API_V1_STR)
 
 if __name__ == "__main__":
-    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)
\ No newline at end of file
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)
diff --git a/requirements.txt b/requirements.txt
index 3d9fcc4..afbefc5 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,6 +2,7 @@ fastapi==0.110.1
 uvicorn==0.29.0
 sqlalchemy==2.0.29
 pydantic==2.6.4
+pydantic-settings==2.2.1
 alembic==1.13.1
 ruff==0.3.2
 python-dotenv==1.0.1
\ No newline at end of file