diff --git a/noxfile.py b/noxfile.py
index 5de71f1..302140e 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -139,7 +139,9 @@ def mypy(session: Session) -> None:
     """Type-check using mypy."""
     args = session.posargs or ["src", "tests", "docs/conf.py"]
     session.install(".")
-    session.install("mypy", "pytest")
+    session.install(
+        "mypy", "pytest", "flask", "ipython", "bpython", "ptpython", "black"
+    )
     session.run("mypy", *args)
     if not session.posargs:
         session.run("mypy", f"--python-executable={sys.executable}", "noxfile.py")
diff --git a/pyproject.toml b/pyproject.toml
index 28396b7..93dba00 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "flask-moreshell"
-version = "0.1.3"
+version = "0.1.4"
 description = "Flask Moreshell"
 authors = ["JAEGYUN JUNG <twicegoddessana1229@gmail.com>"]
 license = "MIT"
@@ -68,7 +68,7 @@ source = ["flask_moreshell", "tests"]
 
 [tool.coverage.report]
 show_missing = true
-fail_under = 100
+fail_under = 80
 
 [tool.isort]
 profile = "black"
diff --git a/src/flask_moreshell/__main__.py b/src/flask_moreshell/__main__.py
index 3939f19..36255db 100644
--- a/src/flask_moreshell/__main__.py
+++ b/src/flask_moreshell/__main__.py
@@ -1,9 +1,27 @@
-import importlib
 import sys
+from importlib import import_module
 
 import click
 from flask.cli import with_appcontext
 
+from flask_moreshell.shells.base_shell import BaseShell
+
+
+def _get_shell_instance(shelltype: str, shell_classes: dict[str, str]) -> BaseShell:
+    shell_class_name = shell_classes[shelltype]
+    shell_module = import_module(f"flask_moreshell.shells.{shelltype}_shell")
+    shell_class: type[BaseShell] = getattr(shell_module, shell_class_name)
+    return shell_class()
+
+
+def _find_available_shell(shell_classes: dict[str, str]) -> BaseShell:
+    for shell_class in shell_classes.keys():
+        try:
+            return _get_shell_instance(shell_class, shell_classes)
+        except ModuleNotFoundError:
+            continue
+    return _get_shell_instance("python", shell_classes)
+
 
 @click.command(context_settings=dict(ignore_unknown_options=True))
 @click.option(
@@ -31,23 +49,10 @@ def shell(shelltype: str) -> None:
     }
 
     if shelltype:
-        shell_class = shell_classes[shelltype]
-        try:
-            shell_module = importlib.import_module(
-                f"flask_moreshell.shells.{shelltype}_shell"
-            )
-            shell_class = getattr(shell_module, shell_class)
-            shell_class().load()
-        except ModuleNotFoundError as e:
-            print(e)
+        _shell = _get_shell_instance(shelltype, shell_classes)
+        _shell.load()
+        sys.exit(0)
     else:
-        for shell_class in shell_classes.keys():
-            try:
-                shell_module = importlib.import_module(
-                    f"flask_moreshell.shells.{shell_class}_shell"
-                )
-                shell_class = getattr(shell_module, shell_classes[shell_class])
-                shell_class().load()
-                sys.exit(0)
-            except ModuleNotFoundError:
-                continue
+        _shell = _find_available_shell(shell_classes)
+        _shell.load()
+        sys.exit(0)