diff --git a/poetry.lock b/poetry.lock
index 2e32138..83e520f 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -173,6 +173,18 @@ category = "dev"
 optional = false
 python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
 
+[[package]]
+name = "fancycompleter"
+version = "0.9.1"
+description = "colorful TAB completion for Python prompt"
+category = "dev"
+optional = false
+python-versions = "*"
+
+[package.dependencies]
+pyreadline = {version = "*", markers = "platform_system == \"Windows\""}
+pyrepl = ">=0.8.2"
+
 [[package]]
 name = "funcsigs"
 version = "1.0.2"
@@ -358,6 +370,23 @@ category = "dev"
 optional = false
 python-versions = ">=2.6"
 
+[[package]]
+name = "pdbpp"
+version = "0.10.2"
+description = "pdb++, a drop-in replacement for pdb"
+category = "dev"
+optional = false
+python-versions = "*"
+
+[package.dependencies]
+fancycompleter = ">=0.8"
+pygments = "*"
+wmctrl = "*"
+
+[package.extras]
+funcsigs = ["funcsigs"]
+testing = ["funcsigs", "pytest"]
+
 [[package]]
 name = "pluggy"
 version = "0.13.1"
@@ -382,11 +411,11 @@ python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
 
 [[package]]
 name = "pygments"
-version = "2.8.0"
+version = "2.5.2"
 description = "Pygments is a syntax highlighting package written in Python."
 category = "dev"
 optional = false
-python-versions = ">=3.5"
+python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
 
 [[package]]
 name = "pyparsing"
@@ -396,6 +425,22 @@ category = "dev"
 optional = false
 python-versions = ">=2.6, !=3.0.*, !=3.1.*, !=3.2.*"
 
+[[package]]
+name = "pyreadline"
+version = "2.1"
+description = "A python implmementation of GNU readline."
+category = "dev"
+optional = false
+python-versions = "*"
+
+[[package]]
+name = "pyrepl"
+version = "0.9.0"
+description = "A library for building flexible command line interfaces"
+category = "dev"
+optional = false
+python-versions = "*"
+
 [[package]]
 name = "pytest"
 version = "4.6.11"
@@ -693,6 +738,14 @@ python-versions = "*"
 [package.dependencies]
 "backports.functools-lru-cache" = {version = ">=1.2.1", markers = "python_version < \"3.2\""}
 
+[[package]]
+name = "wmctrl"
+version = "0.3"
+description = "A tool to programmatically control windows inside X"
+category = "dev"
+optional = false
+python-versions = "*"
+
 [[package]]
 name = "zipp"
 version = "1.2.0"
@@ -711,7 +764,7 @@ testing = ["pathlib2", "unittest2", "jaraco.itertools", "func-timeout"]
 [metadata]
 lock-version = "1.1"
 python-versions = "~2.7 || ~=3.5"
-content-hash = "0d5443bef765d09eecedee39d508ee18afef352e5311628213314a08793edd6a"
+content-hash = "66b3b619f735c9504ddf521624a8f902b6fb71e0d577c662e943087d0a2d66b7"
 
 [metadata.files]
 alabaster = [
@@ -814,6 +867,10 @@ docutils = [
     {file = "docutils-0.16-py2.py3-none-any.whl", hash = "sha256:0c5b78adfbf7762415433f5515cd5c9e762339e23369dbe8000d84a4bf4ab3af"},
     {file = "docutils-0.16.tar.gz", hash = "sha256:c2de3a60e9e7d07be26b7f2b00ca0309c207e06c100f9cc2a94931fc75a478fc"},
 ]
+fancycompleter = [
+    {file = "fancycompleter-0.9.1-py3-none-any.whl", hash = "sha256:dd076bca7d9d524cc7f25ec8f35ef95388ffef9ef46def4d3d25e9b044ad7080"},
+    {file = "fancycompleter-0.9.1.tar.gz", hash = "sha256:09e0feb8ae242abdfd7ef2ba55069a46f011814a80fe5476be48f51b00247272"},
+]
 funcsigs = [
     {file = "funcsigs-1.0.2-py2.py3-none-any.whl", hash = "sha256:330cc27ccbf7f1e992e69fef78261dc7c6569012cf397db8d3de0234e6c937ca"},
     {file = "funcsigs-1.0.2.tar.gz", hash = "sha256:a7bb0f2cf3a3fd1ab2732cb49eba4252c2af4240442415b4abce3b87022a8f50"},
@@ -932,6 +989,9 @@ pbr = [
     {file = "pbr-5.5.1-py2.py3-none-any.whl", hash = "sha256:b236cde0ac9a6aedd5e3c34517b423cd4fd97ef723849da6b0d2231142d89c00"},
     {file = "pbr-5.5.1.tar.gz", hash = "sha256:5fad80b613c402d5b7df7bd84812548b2a61e9977387a80a5fc5c396492b13c9"},
 ]
+pdbpp = [
+    {file = "pdbpp-0.10.2.tar.gz", hash = "sha256:73ff220d5006e0ecdc3e2705d8328d8aa5ac27fef95cc06f6e42cd7d22d55eb8"},
+]
 pluggy = [
     {file = "pluggy-0.13.1-py2.py3-none-any.whl", hash = "sha256:966c145cd83c96502c3c3868f50408687b38434af77734af1e9ca461a4081d2d"},
     {file = "pluggy-0.13.1.tar.gz", hash = "sha256:15b2acde666561e1298d71b523007ed7364de07029219b604cf808bfa1c765b0"},
@@ -941,13 +1001,21 @@ py = [
     {file = "py-1.10.0.tar.gz", hash = "sha256:21b81bda15b66ef5e1a777a21c4dcd9c20ad3efd0b3f817e7a809035269e1bd3"},
 ]
 pygments = [
-    {file = "Pygments-2.8.0-py3-none-any.whl", hash = "sha256:b21b072d0ccdf29297a82a2363359d99623597b8a265b8081760e4d0f7153c88"},
-    {file = "Pygments-2.8.0.tar.gz", hash = "sha256:37a13ba168a02ac54cc5891a42b1caec333e59b66addb7fa633ea8a6d73445c0"},
+    {file = "Pygments-2.5.2-py2.py3-none-any.whl", hash = "sha256:2a3fe295e54a20164a9df49c75fa58526d3be48e14aceba6d6b1e8ac0bfd6f1b"},
+    {file = "Pygments-2.5.2.tar.gz", hash = "sha256:98c8aa5a9f778fcd1026a17361ddaf7330d1b7c62ae97c3bb0ae73e0b9b6b0fe"},
 ]
 pyparsing = [
     {file = "pyparsing-2.4.7-py2.py3-none-any.whl", hash = "sha256:ef9d7589ef3c200abe66653d3f1ab1033c3c419ae9b9bdb1240a85b024efc88b"},
     {file = "pyparsing-2.4.7.tar.gz", hash = "sha256:c203ec8783bf771a155b207279b9bccb8dea02d8f0c9e5f8ead507bc3246ecc1"},
 ]
+pyreadline = [
+    {file = "pyreadline-2.1.win-amd64.exe", hash = "sha256:9ce5fa65b8992dfa373bddc5b6e0864ead8f291c94fbfec05fbd5c836162e67b"},
+    {file = "pyreadline-2.1.win32.exe", hash = "sha256:65540c21bfe14405a3a77e4c085ecfce88724743a4ead47c66b84defcf82c32e"},
+    {file = "pyreadline-2.1.zip", hash = "sha256:4530592fc2e85b25b1a9f79664433da09237c1a270e4d78ea5aa3a2c7229e2d1"},
+]
+pyrepl = [
+    {file = "pyrepl-0.9.0.tar.gz", hash = "sha256:292570f34b5502e871bbb966d639474f2b57fbfcd3373c2d6a2f3d56e681a775"},
+]
 pytest = [
     {file = "pytest-4.6.11-py2.py3-none-any.whl", hash = "sha256:a00a7d79cbbdfa9d21e7d0298392a8dd4123316bfac545075e6f8f24c94d8c97"},
     {file = "pytest-4.6.11.tar.gz", hash = "sha256:50fa82392f2120cc3ec2ca0a75ee615be4c479e66669789771f1758332be4353"},
@@ -1144,6 +1212,9 @@ wcwidth = [
     {file = "wcwidth-0.2.5-py2.py3-none-any.whl", hash = "sha256:beb4802a9cebb9144e99086eff703a642a13d6a0052920003a230f3294bbe784"},
     {file = "wcwidth-0.2.5.tar.gz", hash = "sha256:c4d647b99872929fdb7bdcaa4fbe7f01413ed3d98077df798530e5b04f116c83"},
 ]
+wmctrl = [
+    {file = "wmctrl-0.3.tar.gz", hash = "sha256:d806f65ac1554366b6e31d29d7be2e8893996c0acbb2824bbf2b1f49cf628a13"},
+]
 zipp = [
     {file = "zipp-1.2.0-py2.py3-none-any.whl", hash = "sha256:e0d9e63797e483a30d27e09fffd308c59a700d365ec34e93cc100844168bf921"},
     {file = "zipp-1.2.0.tar.gz", hash = "sha256:c70410551488251b0fee67b460fb9a536af8d6f9f008ad10ac51f615b6a521b1"},
diff --git a/pyproject.toml b/pyproject.toml
index 015842e..fdcf2ce 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -23,6 +23,7 @@ Sphinx = {version = "~=3.5.0", python = "~=3.5"}
 sphinx-rtd-theme = {version = "~=0.5.1", python = "~=3.5"}
 vulture = {version = "~=2.3", python = "~=3.6"}
 bandit = {version = "~=1.7.0", python = "~=3.6"}
+pdbpp = "^0.10.2"
 
 [build-system]
 requires = ["poetry-core>=1.0.0", "Cython", "setuptools"]