diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ad4a1f1
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,176 @@
+# Created by https://www.toptal.com/developers/gitignore/api/python
+# Edit at https://www.toptal.com/developers/gitignore?templates=python
+
+### Python ###
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+share/python-wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+*.py,cover
+.hypothesis/
+.pytest_cache/
+cover/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+db.sqlite3-journal
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+.pybuilder/
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+#   For a library or package, you might want to ignore these files since the code is
+#   intended to run in multiple environments; otherwise, check them in:
+# .python-version
+
+# pipenv
+#   According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control.
+#   However, in case of collaboration, if having platform-specific dependencies or dependencies
+#   having no cross-platform support, pipenv may install dependencies that don't work, or not
+#   install all needed dependencies.
+#Pipfile.lock
+
+# poetry
+#   Similar to Pipfile.lock, it is generally recommended to include poetry.lock in version control.
+#   This is especially recommended for binary packages to ensure reproducibility, and is more
+#   commonly ignored for libraries.
+#   https://python-poetry.org/docs/basic-usage/#commit-your-poetrylock-file-to-version-control
+#poetry.lock
+
+# pdm
+#   Similar to Pipfile.lock, it is generally recommended to include pdm.lock in version control.
+#pdm.lock
+#   pdm stores project-wide configurations in .pdm.toml, but it is recommended to not include it
+#   in version control.
+#   https://pdm.fming.dev/#use-with-ide
+.pdm.toml
+
+# PEP 582; used by e.g. github.com/David-OConnor/pyflow and github.com/pdm-project/pdm
+__pypackages__/
+
+# Celery stuff
+celerybeat-schedule
+celerybeat.pid
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+
+# Spyder project settings
+.spyderproject
+.spyproject
+
+# Rope project settings
+.ropeproject
+
+# mkdocs documentation
+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/
+
+# pytype static type analyzer
+.pytype/
+
+# Cython debug symbols
+cython_debug/
+
+# PyCharm
+#  JetBrains specific template is maintained in a separate JetBrains.gitignore that can
+#  be found at https://github.com/github/gitignore/blob/main/Global/JetBrains.gitignore
+#  and can be added to the global gitignore or merged into this file.  For a more nuclear
+#  option (not recommended) you can uncomment the following to ignore the entire idea folder.
+#.idea/
+
+### Python Patch ###
+# Poetry local configuration file - https://python-poetry.org/docs/configuration/#local-configuration
+poetry.toml
+
+# ruff
+.ruff_cache/
+
+# LSP config files
+pyrightconfig.json
+
+# End of https://www.toptal.com/developers/gitignore/api/python
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..122816a
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2025 Nikita Vandyshev
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/src/fast_pow.py b/src/fast_pow.py
index 1ba1dc1..8946b73 100644
--- a/src/fast_pow.py
+++ b/src/fast_pow.py
@@ -1,6 +1,15 @@
 def fastPow(number, power):
-    result = number
-    while power != 1:
-        result *= result
+    if not isinstance(power, int):
+        raise ValueError("Power must be integer")
+    if power < 0:
+        raise ValueError("Power must be non-negative")
+    if power == 0:
+        return 1 
+    result = 1
+    base = number
+    while power > 0:
+        if power % 2 == 1:
+            result *= base
+        base *= base
         power = power // 2
-    return result
+    return result
\ No newline at end of file
diff --git a/src/luhn.py b/src/luhn.py
index 11d993c..1d62a0c 100644
--- a/src/luhn.py
+++ b/src/luhn.py
@@ -1,14 +1,19 @@
-def luhnСheck(cardNumber):
-    digits = [int(d) for d in str(cardNumber) if d.isdigit()]
-    control = digits.pop()
-    parity = (len(digits))%2
-    total = 0
-    for i in range(len(digits)):
-        if i % 2 == parity:
-            doubled = digits[i] * 2
-            if doubled > 9:
-                doubled -= 9
-            total += doubled
-        else:
-            total += digits[i]
-    return (total + control) % 10 == 0
+def luhnCheck(cardNumber):
+    try:
+        digits = [int(d) for d in str(cardNumber) if d.isdigit()]
+        if len(digits) < 2:
+            return False
+        control = digits.pop()
+        parity = len(digits) % 2
+        total = 0
+        for i in range(len(digits)):
+            if i % 2 == parity:
+                doubled = digits[i] * 2
+                if doubled > 9:
+                    doubled -= 9
+                total += doubled
+            else:
+                total += digits[i]
+        return (total + control) % 10 == 0
+    except Exception:
+        return False
\ No newline at end of file
diff --git a/test/test_fast_pow.py b/test/test_fast_pow.py
index 5e4aebd..3e1eaba 100644
--- a/test/test_fast_pow.py
+++ b/test/test_fast_pow.py
@@ -7,3 +7,26 @@ def test_two_power_two():
 
 def test_negative():
     assert fastPow(-1, 4) == 1
+
+def test_zero_power():
+    assert fastPow(5, 0) == 1
+
+def test_negative_power():
+    try:
+        fastPow(2, -1)
+        assert False
+    except ValueError:
+        pass
+
+def test_invalid_power_type():
+    try:
+        fastPow(2, 2.5)
+        assert False
+    except ValueError:
+        pass
+    
+def test_additional_cases():
+    assert fastPow(2, 3) == 8
+    assert fastPow(1, 100) == 1
+    assert fastPow(0, 5) == 0
+    assert fastPow(-2, 3) == -8