diff --git a/install.sh b/install.sh
index 8b9b780..8d1b082 100755
--- a/install.sh
+++ b/install.sh
@@ -1,3 +1,11 @@
 #!/bin/bash
 
-pipx install --python python3.9 --force $1 .
+# optional pipx arguments can be passed as the first argument
+# e.g. ./install.sh --verbose --editable
+
+# Remove existing installs
+pipx uninstall ClayCodeTests > /dev/null 2>&1
+pipx uninstall ClayCode > /dev/null 2>&1
+
+# Install the package
+pipx install --python python3.10 --force $1 .
diff --git a/package/ClayCode/core/gmx.py b/package/ClayCode/core/gmx.py
index b8bb838..819a7f2 100644
--- a/package/ClayCode/core/gmx.py
+++ b/package/ClayCode/core/gmx.py
@@ -259,7 +259,7 @@ def get_mdp_parameter_file(
                 file_or_str=mdp_str,
                 freeze_dims=freeze_dims,
             )
-        if define is not None:
+        if define is not None and not isinstance(define, bool):
             if isinstance(define, str):
                 define_str = f"-D{define}"
             else:
@@ -267,6 +267,7 @@ def get_mdp_parameter_file(
                     define_str = " ".join(
                         list(map(lambda d: f"-D{d}", definition))
                     )
+                pass
             mdp_str = set_mdp_parameter("define", define_str, mdp_str)
         mdp_str = re.sub(
             "(^|\n)[^\n]*?\s*?=\s*?\n",