diff --git a/Makefile b/Makefile
index af615e9..f9e5447 100644
--- a/Makefile
+++ b/Makefile
@@ -2,39 +2,57 @@ SHELL := bash
 PATH := ./venv/bin:${PATH}
 PYTHON=python3.7
 PROJECT=cep
-isort = isort -rc -ac $(PROJECT) tests setup.py
+isort = isort $(PROJECT) tests setup.py
 black = black -S -l 79 --target-version py37 $(PROJECT) tests setup.py
 
-all: test
+.PHONY: all
+all: testt
 
 venv:
-		$(PYTHON) -m venv --prompt $(PROJECT) venv
-		pip install -qU pip
+	$(PYTHON) -m venv --prompt $(PROJECT) venv
+	pip install -qU pip
 
-install-test:
-		pip install -q .[test]
+.PHONY: install
+install:
+	pip install -qU -r requirements.txt	
 
+.PHONY: install-test
+install-test: install
+	pip install -qU -r requirements-test.txt
+
+.PHONY: test
 test: clean install-test lint
-		python setup.py test
+	pytest
 
+.PHONY: format
 format:
-		$(isort)
-		$(black)
+	$(isort)
+	$(black)
 
+.PHONY: lint
 lint:
-		$(isort) --check-only
-		$(black) --check
-		flake8 $(PROJECT) tests setup.py
+	$(isort) --check-only
+	$(black) --check
+	flake8 $(PROJECT) tests setup.py
+	mypy $(PROJECT) tests
 
+.PHONY: clean
 clean:
-		find . -name '*.pyc' -exec rm -f {} +
-		find . -name '*.pyo' -exec rm -f {} +
-		find . -name '*~' -exec rm -f {} +
-		rm -rf build dist $(PROJECT).egg-info
-
-release: clean
-		python setup.py sdist bdist_wheel
-		twine upload dist/*
-
-
-.PHONY: all install-test release test clean-pyc
+	rm -rf `find . -name __pycache__`
+	rm -f `find . -type f -name '*.py[co]' `
+	rm -f `find . -type f -name '*~' `
+	rm -f `find . -type f -name '.*~' `
+	rm -rf .cache
+	rm -rf .pytest_cache
+	rm -rf .mypy_cache
+	rm -rf htmlcov
+	rm -rf *.egg-info
+	rm -f .coverage
+	rm -f .coverage.*
+	rm -rf build
+	rm -rf dist
+
+.PHONY: release
+release: test clean
+	python setup.py sdist bdist_wheel
+	twine upload dist/*
diff --git a/cep/__init__.py b/cep/__init__.py
index a9bb1bb..0075cfe 100644
--- a/cep/__init__.py
+++ b/cep/__init__.py
@@ -1,5 +1,6 @@
-__all__ = ['Cuenta', 'Client', 'Transferencia']
+__all__ = ['__version__', 'Cuenta', 'Client', 'Transferencia']
 
 from .client import Client
 from .cuenta import Cuenta
 from .transferencia import Transferencia
+from .version import __version__
diff --git a/cep/py.typed b/cep/py.typed
new file mode 100644
index 0000000..e69de29
diff --git a/cep/transferencia.py b/cep/transferencia.py
index a08897b..cd3f469 100644
--- a/cep/transferencia.py
+++ b/cep/transferencia.py
@@ -56,7 +56,7 @@ def validar(
             receptor=receptor,
             sello=resp.get('sello'),
         )
-        transferencia.__client = client
+        setattr(transferencia, '__client', client)
         return transferencia
 
     def descargar(self, formato: str = 'PDF') -> bytes:
@@ -97,9 +97,8 @@ def _validar(
             monto=monto,
         )
         resp = client.post('/valida.do', request_body)
-        if b'no encontrada' in resp:
-            client = None  # No pudó validar
-        return client
+        # None si no pudó validar
+        return client if b'no encontrada' not in resp else None
 
     @staticmethod
     def _descargar(client: Client, formato: str = 'PDF') -> bytes:
diff --git a/cep/version.py b/cep/version.py
new file mode 100644
index 0000000..7525d19
--- /dev/null
+++ b/cep/version.py
@@ -0,0 +1 @@
+__version__ = '0.1.4'
diff --git a/requirements-test.txt b/requirements-test.txt
new file mode 100644
index 0000000..756c2c3
--- /dev/null
+++ b/requirements-test.txt
@@ -0,0 +1,7 @@
+pytest==5.4.3
+pytest-vcr==1.0.2
+pytest-cov==2.10.0
+black==19.10b0
+flake8==3.8.3
+isort[pipfile]==4.3.21
+mypy==0.790
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..f973110
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,4 @@
+requests==2.24.0
+clabe==1.2.0
+lxml==4.5.1
+dataclasses>=0.6;python_version<"3.7"
diff --git a/setup.cfg b/setup.cfg
index 441024b..4718c66 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -3,3 +3,28 @@ test=pytest
 
 [tool:pytest]
 addopts = -p no:warnings -v --cov-report term-missing --cov=cep
+
+[flake8]
+inline-quotes = '
+multiline-quotes = """
+
+[isort]
+multi_line_output=3
+include_trailing_comma=True
+force_grid_wrap=0
+combine_as_imports=True
+
+[mypy-lxml]
+ignore_missing_imports = true
+
+[mypy-clabe]
+ignore_missing_imports = true
+
+[mypy-pytest]
+ignore_missing_imports = true
+
+[coverage:report]
+precision = 2
+exclude_lines =
+    pragma: no cover
+    if TYPE_CHECKING:
diff --git a/setup.py b/setup.py
index 8b37b2f..fbed658 100644
--- a/setup.py
+++ b/setup.py
@@ -1,4 +1,8 @@
-import setuptools
+from importlib.machinery import SourceFileLoader
+
+from setuptools import find_packages, setup
+
+version = SourceFileLoader('version', 'cep/version.py').load_module()
 
 install_requirements = [
     'requests==2.24.0',
@@ -7,36 +11,25 @@
     'dataclasses>=0.6;python_version<"3.7"',
 ]
 
-test_requires = (
-    [
-        'pytest==5.4.3',
-        'pytest-vcr==1.0.2',
-        'pytest-cov==2.10.0',
-        'black==19.10b0',
-        'flake8==3.8.3',
-        'isort[pipfile]==4.3.21',
-    ],
-)
 
 with open('README.md', 'r') as f:
     long_description = f.read()
 
 
-setuptools.setup(
+setup(
     name='cepmex',
-    version='0.1.3',
+    version=version.__version__,
     author='Cuenca',
     author_email='dev@cuenca.com',
     description='CEP client library',
     long_description=long_description,
     long_description_content_type='text/markdown',
     url='https://github.com/cuenca-mx/cep-python',
-    packages=setuptools.find_packages(),
+    packages=find_packages(),
+    include_package_data=True,
+    package_data=dict(cep=['py.typed']),
     python_requires='>=3.7',
     install_requires=install_requirements,
-    setup_requires=['pytest-runner'],
-    tests_require=test_requires,
-    extras_require=dict(test=test_requires),
     classifiers=[
         'Programming Language :: Python :: 3.7',
         'License :: OSI Approved :: MIT License',