diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index d5e48fb..a81d771 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -1,6 +1,6 @@
 variables:
-  deps.space: 'conda requests xonsh lazyasd tqdm ruamel.yaml pytest pytest-timeout virtualenv pip pytest-azurepipelines'
-  deps.comma: 'conda,requests,xonsh,lazyasd,tqdm,ruamel.yaml,pytest,pytest-timeout,virtualenv,pip,pytest-azurepipelines'
+  deps.space: 'conda requests xonsh lazyasd tqdm ruamel.yaml pytest pytest-timeout virtualenv pip pytest-azurepipelines dataclasses'
+  deps.comma: 'conda,requests,xonsh,lazyasd,tqdm,ruamel.yaml,pytest,pytest-timeout,virtualenv,pip,pytest-azurepipelines,dataclasses'
 
 jobs:
 - job: windows
diff --git a/conda_press/condatools.xsh b/conda_press/condatools.xsh
index f9b5345..2d02122 100644
--- a/conda_press/condatools.xsh
+++ b/conda_press/condatools.xsh
@@ -644,9 +644,11 @@ class ArtifactInfo:
             with ${...}.swap(RAISE_SUBPROC_ERROR=True):
                 ![strip --strip-all --preserve-dates --enable-deterministic-archives @(absname)]
 
-    def replace_symlinks(self, strip_symbols=self.config.strip_symbols):
+    def replace_symlinks(self, strip_symbols=None):
         # this is needed because of https://github.com/pypa/pip/issues/5919
         # this has to walk the package deps in some cases.
+        if strip_symbols is None:
+            strip_symbols = self.config.strip_symbols
         for f in self.files:
             absname = os.path.join(self.artifactdir, f)
             if not os.path.islink(absname):
@@ -770,7 +772,7 @@ def artifact_ref_dependency_tree_to_wheels(artifact_ref, config=None, seen=None)
     top_name = name_from_ref(artifact_ref)
     top_found = False
 
-    solver = Solver("<none>", config.channels, subdirs=config.subdirs, specs_to_add=(artifact_ref,))
+    solver = Solver("<none>", config.channels, subdirs=config.subdir, specs_to_add=(artifact_ref,))
     package_recs = solver.solve_final_state()
 
     if config.skip_python:
diff --git a/conda_press/config.py b/conda_press/config.py
index 34e3d6c..053bfdc 100644
--- a/conda_press/config.py
+++ b/conda_press/config.py
@@ -2,8 +2,7 @@
 import platform
 import tempfile
 from dataclasses import dataclass, field
-from pathlib import Path
-from typing import List, Set
+from typing import Union, List, Set, Tuple
 
 CACHE_DIR = os.path.join(tempfile.gettempdir(), "artifact-cache")
 DEFAULT_CHANNELS = ("conda-forge", "anaconda", "main", "r")
@@ -20,11 +19,11 @@
 
 @dataclass(init=True, repr=True, eq=True, order=False)
 class Config:
-    subdir: (str, tuple)
-    _subdir: tuple = field(init=False, repr=False)
-    output: (str, Path) = field(default=None)
-    _channels: List[str] = field(init=False, repr=False)
-    channels: List[str] = field(default=None)
+    subdir: Union[str, Tuple[str, ...]]
+    channels: List[str]
+    output: str = field(default=None)
+    _subdir: Tuple[str, ...] = field(init=False, repr=False)
+    _channels: List[str] = field(init=False, repr=False, default_factory=list)
     exclude_deps: Set[str] = field(default_factory=set)
     add_deps: Set[str] = field(default_factory=set)
     skip_python: bool = False
@@ -43,14 +42,28 @@ def channels(self, list_channels: List[str]):
         self._channels = list_channels
 
     @property
-    def subdir(self) -> tuple:
+    def subdir(self) -> Tuple[str, ...]:
         return self._subdir + ("noarch",)
 
     @subdir.setter
-    def subdir(self, new_subdir: (tuple, str)):
+    def subdir(self, new_subdir: Union[Tuple[str, ...], str]):
         if isinstance(new_subdir, str):
-            new_subdir = (new_subdir,)
-        self._subdir = new_subdir
+            self._subdir = (new_subdir,)
+        else:
+            self._subdir = new_subdir
 
-    def clean_deps(self, list_deps):
+    def clean_deps(self, list_deps: Union[Set[str], List[str]]) -> Set[str]:
+        """This method is responsible to remove the excluded dependencies and
+        add the new dependencies in a list of dependencies received.
+
+        Parameters
+        ----------
+        list_deps : array_like
+            Receives a set or a list of dependencies
+
+        Returns
+        -------
+        set
+            Returns a set with the dependencies.
+        """
         return set(list_deps).union(self.add_deps).difference(self.exclude_deps)
diff --git a/setup.py b/setup.py
index 761d963..2b3f601 100755
--- a/setup.py
+++ b/setup.py
@@ -30,8 +30,8 @@ def main():
         package_dir={'conda_press': 'conda_press'},
         package_data={'conda_press': ['*.xsh']},
         scripts=scripts,
-        install_requires=['xonsh', 'lazyasd', 'ruamel.yaml', 'tqdm', 'requests'],
-        python_requires=">=3.5",
+        install_requires=['xonsh', 'lazyasd', 'ruamel.yaml', 'tqdm', 'requests', 'dataclasses'],
+        python_requires=">=3.6",
         zip_safe=False,
         )
     setup(**skw)
diff --git a/tests/test_config.py b/tests/test_config.py
index 253b289..5d52c45 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -1,10 +1,12 @@
-from conda_press.config import Config
+import pytest
 
+from conda_press.config import Config
 
-def test_fields(tmpdir):
-    config_press = Config(
-        subdir=str(tmpdir),
-        output=str(tmpdir),
+@pytest.fixture
+def config_obj(tmpdir):
+    return Config(
+        subdir="SUBDIR",
+        output="OUTPUT",
         channels=["FOO-CHANNEL", "CHANNEL2"],
         fatten=True,
         skip_python=True,
@@ -15,17 +17,27 @@ def test_fields(tmpdir):
         only_pypi=True,
         include_requirements=False,
     )
+
+
+def test_fields(config_obj):
     assert (
-        config_press.channels.sort()
+        config_obj.channels.sort()
         == ["FOO-CHANNEL", "conda-forge", "anaconda", "main", "r"].sort()
     )
-    assert config_press.subdir == (str(tmpdir), "noarch")
-    assert config_press.output == str(tmpdir)
-    assert config_press.fatten
-    assert config_press.skip_python
-    assert not config_press.strip_symbols
-    assert config_press.merge
-    assert config_press.exclude_deps == {"EXCLUDE1", "EXCLUDE2"}
-    assert config_press.add_deps == {"ADD1", "ADD2"}
-    assert config_press.only_pypi
-    assert not config_press.include_requirements
+    assert config_obj.subdir == ("SUBDIR", "noarch")
+    assert config_obj.output == "OUTPUT"
+    assert config_obj.fatten
+    assert config_obj.skip_python
+    assert not config_obj.strip_symbols
+    assert config_obj.merge
+    assert config_obj.exclude_deps == {"EXCLUDE1", "EXCLUDE2"}
+    assert config_obj.add_deps == {"ADD1", "ADD2"}
+    assert config_obj.only_pypi
+    assert not config_obj.include_requirements
+
+
+def test_clean_deps(config_obj):
+    config_obj.add_deps = {"DEP1", "DEP2", "DEP3", "DEP4"}
+    config_obj.exclude_deps = {"DEP2", "DEP4"}
+    all_deps = ["DEP0", "DEP1", "DEP2", "DEP5"]
+    assert config_obj.clean_deps(all_deps) == {"DEP0", "DEP1", "DEP3", "DEP5"}