diff --git a/app/models/constraint.py b/app/models/constraint.py
index 84eb1b2..2c84a60 100644
--- a/app/models/constraint.py
+++ b/app/models/constraint.py
@@ -5,5 +5,5 @@ from models.attribute import Attribute
 
 class Constraint(BaseModel):
   reference_attribute: Attribute
-  minimum: int
-  maximum: int
+  minimum: float
+  maximum: float
diff --git a/app/models/item.py b/app/models/item.py
index 86beb61..71bffcf 100644
--- a/app/models/item.py
+++ b/app/models/item.py
@@ -16,3 +16,15 @@ class Item(BaseModel):
 
   def irf(self, solver_run, theta):
     return ItemResponseFunction(solver_run.irt_model).calculate(b_param=self.b_param,theta=theta)
+
+  def get_attribute(self, id, value):
+    for attribute in self.attributes:
+      if attribute.id == id and attribute.value == value:
+        return attribute.value
+    return False
+
+  def attribute_exists(self, id, value):
+    for attribute in self.attributes:
+      if attribute.id == id and attribute.value == value:
+        return True
+    return False
\ No newline at end of file