fix: callback for _coerce_fee

Signed-off-by: tech0priyanshu <priyanshuyadv101106@gmail.com>

Author: tech0priyanshu

src/hiero_sdk_python/client/client.py

@@ -293,12 +293,12 @@ def set_max_transaction_fee(
         self,
         max_transaction_fee: int | float | Decimal | Hbar,
     ) -> Client:
-        """Sets the default maximum Hbar fee allowed for any transaction executed by this client."""
-        value = max_transaction_fee if isinstance(max_transaction_fee, Hbar) else Hbar(max_transaction_fee)
-
-        if value < Hbar(0):
+        """
+        Sets the default maximum Hbar fee allowed for any  transaction executed by this client.
+        """
+        value = Hbar._coerce_fee(max_transaction_fee)
+        if value < Hbar.ZERO:
             raise ValueError("max_transaction_fee must be non-negative")
-
         self.default_max_transaction_fee = value
         return self
 

src/hiero_sdk_python/hbar.py

@@ -83,6 +83,21 @@ def negated(self) -> Hbar:
         """
         return Hbar.from_tinybars(-self._amount_in_tinybar)
 
+    @staticmethod
+    def _coerce_fee(value: int | float | Decimal | Hbar) -> Hbar:
+        """
+        Coerce a value to an Hbar instance. Accepts int, float, Decimal, or Hbar (but not bool).
+        Args:
+            value: The value to coerce.
+        Returns:
+            Hbar: An Hbar instance.
+        Raises:
+            TypeError: If value is not a valid type.
+        """
+        if isinstance(value, bool) or not isinstance(value, (int, float, Decimal, Hbar)):
+            raise TypeError(f"value must be int, float, Decimal, or Hbar, got {type(value).__name__}")
+        return value if isinstance(value, Hbar) else Hbar(value)
+
     @classmethod
     def of(cls, amount: int | float | Decimal, unit: HbarUnit) -> Hbar:
         """

src/hiero_sdk_python/transaction/transaction.py

@@ -1,7 +1,6 @@
 from __future__ import annotations
 
 import hashlib
-from decimal import Decimal
 from typing import TYPE_CHECKING, Literal, overload
 
 from hiero_sdk_python.account.account_id import AccountId
@@ -795,19 +794,10 @@ def from_bytes(transaction_bytes: bytes):
         )
 
     def set_max_transaction_fee(self, max_transaction_fee):
-        # Accept int, float, Decimal, or Hbar (but not bool)
         self._require_not_frozen()
-
-        if isinstance(max_transaction_fee, bool) or not isinstance(max_transaction_fee, (int, float, Decimal, Hbar)):
-            raise TypeError(
-                f"max_transaction_fee must be int, float, Decimal, or Hbar, got {type(max_transaction_fee).__name__}"
-            )
-
-        value = max_transaction_fee if isinstance(max_transaction_fee, Hbar) else Hbar(max_transaction_fee)
-
-        if value < Hbar(0):
+        value = Hbar._coerce_fee(max_transaction_fee)
+        if value < Hbar.ZERO:
             raise ValueError("max_transaction_fee must be non-negative")
-
         self.transaction_fee = value
         return self