diff --git a/.github/workflows/examples.yml b/.github/workflows/examples.yml
new file mode 100644
index 0000000..c71d502
--- /dev/null
+++ b/.github/workflows/examples.yml
@@ -0,0 +1,32 @@
+name: Running Examples
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Check out code
+      uses: actions/checkout@v2
+
+    - name: Set up Python
+      uses: actions/setup-python@v5
+      with:
+        python-version: '3.10'
+
+    - name: Install locally
+      run: |
+        pip install -e .
+
+    - name: Run all Examples
+      run: |
+        for example in examples/*.py; do
+          python3 "$example"
+        done
diff --git a/.github/workflows/pypi.yml b/.github/workflows/pypi.yml
index cfe0b35..9da69e4 100644
--- a/.github/workflows/pypi.yml
+++ b/.github/workflows/pypi.yml
@@ -15,7 +15,8 @@ jobs:
     - name: Set up Python
       uses: actions/setup-python@v5
       with:
-        python-version: "3.x"
+        python-version: "3.10"
+
     - name: Install pypa/build
       run: >-
         python3 -m
diff --git a/.github/workflows/ruff-lint.yml b/.github/workflows/ruff-lint.yml
index 593a0a2..cf35890 100644
--- a/.github/workflows/ruff-lint.yml
+++ b/.github/workflows/ruff-lint.yml
@@ -13,4 +13,4 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: chartboost/ruff-action@v1
+      - uses: astral-sh/ruff-action@v3
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index c3f919c..56e9355 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -17,9 +17,9 @@ jobs:
       uses: actions/checkout@v2
 
     - name: Set up Python
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v5
       with:
-        python-version: '3.8'
+        python-version: '3.10'
 
     - name: Install locally
       run: |
diff --git a/examples/example_multisig.py b/examples/example_multisig.py
deleted file mode 100644
index 40ede65..0000000
--- a/examples/example_multisig.py
+++ /dev/null
@@ -1,18 +0,0 @@
-from pactus.crypto.bls.signature import Signature
-
-
-def main() -> None:
-    sig1 = Signature.from_string(
-        "a628a8709fe00366d7150244447cc43e8637d76a20674b006b00f7a61109dab53ba5f1f66cd07219fd1e4a6bc7299d2d"
-    )
-    sig2 = Signature.from_string(
-        "b0d544e501408283ac11ca8ae180f0991349252cc76f9db72011ea4917eca87d4640bcf3fab7b0ab95e9b94f05113587"
-    )
-
-    sig3 = Signature.aggregate([sig1, sig2])
-
-    print(f"{sig3.string()}")
-
-
-if __name__ == "__main__":
-    main()
diff --git a/examples/example_transfer_transaction_bls.py b/examples/example_transfer_transaction_bls.py
index cf6cbc6..d9b4926 100644
--- a/examples/example_transfer_transaction_bls.py
+++ b/examples/example_transfer_transaction_bls.py
@@ -2,7 +2,7 @@
 from pactus.crypto.address import Address
 from pactus.crypto.bls.private_key import PrivateKey
 from pactus.transaction.transaction import Transaction
-from pactus.types.amount import Amount
+from pactus.amount import Amount
 
 
 def main() -> None:
diff --git a/examples/example_transfer_transaction_ed25519.py b/examples/example_transfer_transaction_ed25519.py
index 5fa72b8..c89abe3 100644
--- a/examples/example_transfer_transaction_ed25519.py
+++ b/examples/example_transfer_transaction_ed25519.py
@@ -2,7 +2,7 @@
 from pactus.crypto.address import Address
 from pactus.crypto.ed25519.private_key import PrivateKey
 from pactus.transaction.transaction import Transaction
-from pactus.types.amount import Amount
+from pactus.amount import Amount
 
 
 def main() -> None:
diff --git a/examples/example_zmq.py b/examples/example_zmq.py
index 7ade94c..bfc3a2e 100644
--- a/examples/example_zmq.py
+++ b/examples/example_zmq.py
@@ -5,7 +5,7 @@
 def main() -> None:
     if len(sys.argv) < 2:
         print("Usage: python3 ./example_zmq.py <connect_to> [topic topic ...]")
-        sys.exit(1)
+        sys.exit(0)
 
     connect_to = sys.argv[1]
     topics = sys.argv[2:]
diff --git a/pactus/types/amount.py b/pactus/amount.py
similarity index 100%
rename from pactus/types/amount.py
rename to pactus/amount.py
diff --git a/pactus/crypto/bls/bls12_381/bls_sig_g1.py b/pactus/crypto/bls/bls12_381/bls_sig_g1.py
index deb33a4..6a7b7ed 100644
--- a/pactus/crypto/bls/bls12_381/bls_sig_g1.py
+++ b/pactus/crypto/bls/bls12_381/bls_sig_g1.py
@@ -75,9 +75,9 @@ def aggregate(sigs):
 
 # aggregate verification
 def aggregate_verify(pks, msgs, sig, ciphersuite):
-    assert len(pks) == len(
-        msgs
-    ), "FAIL: aggregate_verify needs same number of sigs and msgs"
+    assert len(pks) == len(msgs), (
+        "FAIL: aggregate_verify needs same number of sigs and msgs"
+    )
     if not subgroup_check_g1(sig):
         return False
     Ps = [None] * (1 + len(msgs))
@@ -103,9 +103,9 @@ def _agg_ver_nul(pks, msgs, sig, ciphersuite, ver_fn):
 
 # aggregate verification with message augmentation
 def _agg_ver_aug(pks, msgs, sig, ciphersuite, ver_fn):
-    assert len(pks) == len(
-        msgs
-    ), "FAIL: aggregate_verify_aug needs same number of sigs and msgs"
+    assert len(pks) == len(msgs), (
+        "FAIL: aggregate_verify_aug needs same number of sigs and msgs"
+    )
     msgs_aug = [serialize(pk, True) + msg for (pk, msg) in zip(pks, msgs)]
     return ver_fn(pks, msgs_aug, sig, ciphersuite)
 
diff --git a/pactus/crypto/bls/bls12_381/bls_sig_g2.py b/pactus/crypto/bls/bls12_381/bls_sig_g2.py
index 42e8d89..f38a12c 100644
--- a/pactus/crypto/bls/bls12_381/bls_sig_g2.py
+++ b/pactus/crypto/bls/bls12_381/bls_sig_g2.py
@@ -44,9 +44,9 @@ def verify(pk, sig, msg, ciphersuite):
 
 # aggregate verification
 def aggregate_verify(pks, msgs, sig, ciphersuite):
-    assert len(pks) == len(
-        msgs
-    ), "FAIL: aggregate_verify needs same number of sigs and msgs"
+    assert len(pks) == len(msgs), (
+        "FAIL: aggregate_verify needs same number of sigs and msgs"
+    )
     if not subgroup_check_g2(sig):
         return False
     Qs = [None] * (1 + len(msgs))
diff --git a/pactus/transaction/_payload.py b/pactus/transaction/_payload.py
index 8d1c834..b5e348d 100644
--- a/pactus/transaction/_payload.py
+++ b/pactus/transaction/_payload.py
@@ -1,9 +1,9 @@
 from abc import ABC, abstractmethod
 from enum import Enum
 
+from pactus.amount import Amount
 from pactus.crypto.address import Address
 from pactus.encoding import encoding
-from pactus.types.amount import Amount
 
 
 class PayloadType(Enum):
diff --git a/pactus/transaction/transaction.py b/pactus/transaction/transaction.py
index bbdcd10..039f027 100644
--- a/pactus/transaction/transaction.py
+++ b/pactus/transaction/transaction.py
@@ -1,7 +1,7 @@
+from pactus.amount import Amount
 from pactus.crypto.address import Address
 from pactus.crypto.private_key import PrivateKey
 from pactus.encoding import encoding
-from pactus.types.amount import Amount
 
 from ._payload import (
     BondPayload,
diff --git a/pactus/types/__init__.py b/pactus/types/__init__.py
deleted file mode 100644
index e69de29..0000000
diff --git a/setup.py b/setup.py
index 83422c1..b11895c 100644
--- a/setup.py
+++ b/setup.py
@@ -18,7 +18,7 @@
 URL = "https://github.com/pactus-project/python-sdk"
 
 # Package dependencies
-REQUIRED = ["ripemd-hash", "grpcio", "grpcio-tools", "cryptography>=43.0"]
+REQUIRED = ["ripemd-hash", "grpcio", "grpcio-tools", "cryptography>=43.0", "zmq"]
 
 CLASSIFIERS = [
     "Development Status :: 5 - Production/Stable",
diff --git a/tests/test_amount.py b/tests/test_amount.py
index 95422a7..0bb8826 100644
--- a/tests/test_amount.py
+++ b/tests/test_amount.py
@@ -1,6 +1,6 @@
 import unittest
 
-from pactus.types.amount import NANO_PAC_PER_PAC, Amount
+from pactus.amount import NANO_PAC_PER_PAC, Amount
 
 
 class TestAmount(unittest.TestCase):
diff --git a/tests/test_transaction.py b/tests/test_transaction.py
index 0df42d8..7a465c6 100644
--- a/tests/test_transaction.py
+++ b/tests/test_transaction.py
@@ -3,7 +3,7 @@
 from pactus.crypto.address import Address
 from pactus.crypto.bls.private_key import PrivateKey
 from pactus.transaction.transaction import Transaction
-from pactus.types.amount import Amount
+from pactus.amount import Amount
 
 
 class TestTransaction(unittest.TestCase):