fix ruff error

Author: ArslanSaleem

pandasai/data_loader/semantic_layer_schema.py

@@ -47,7 +47,9 @@ class Column(BaseModel):
     name: str = Field(..., description="Name of the column.")
     type: Optional[str] = Field(None, description="Data type of the column.")
     description: Optional[str] = Field(None, description="Description of the column")
-    expression: Optional[str] = Field(None, description="Aggregation expression (avg, min, max, sum)")
+    expression: Optional[str] = Field(
+        None, description="Aggregation expression (avg, min, max, sum)"
+    )
     alias: Optional[str] = Field(None, description="Alias for the column")
 
     @field_validator("type")
@@ -73,8 +75,12 @@ def is_expression_valid(cls, expr: str) -> Optional[str]:
 
 class Relation(BaseModel):
     name: Optional[str] = Field(None, description="Name of the relationship.")
-    description: Optional[str] = Field(None, description="Description of the relationship.")
-    from_: str = Field(..., alias="from", description="Source column for the relationship.")
+    description: Optional[str] = Field(
+        None, description="Description of the relationship."
+    )
+    from_: str = Field(
+        ..., alias="from", description="Source column for the relationship."
+    )
     to: str = Field(..., description="Target column for the relationship.")