diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000..b7690a2
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,9 @@
+First of all, thank you for contributing to Blueprint.
+
+If you learn something useful, please add it to this file.
+
+# Run the test suite
+
+```
+python -m unittest
+```
diff --git a/blueprintcompiler/language/imports.py b/blueprintcompiler/language/imports.py
index 682f8cd..4fac192 100644
--- a/blueprintcompiler/language/imports.py
+++ b/blueprintcompiler/language/imports.py
@@ -31,16 +31,17 @@ class GtkDirective(AstNode):
 
     @validate("version")
     def gtk_version(self):
-        if self.tokens["version"] not in ["4.0"]:
+        version = self.tokens["version"]
+        if version not in ["4.0"]:
             err = CompileError("Only GTK 4 is supported")
-            if self.tokens["version"].startswith("4"):
+            if version and version.startswith("4"):
                 err.hint("Expected the GIR version, not an exact version number. Use 'using Gtk 4.0;'.")
             else:
                 err.hint("Expected 'using Gtk 4.0;'")
             raise err
 
         try:
-            gir.get_namespace("Gtk", self.tokens["version"])
+            gir.get_namespace("Gtk", version)
         except CompileError as e:
             raise CompileError(
                 "Could not find GTK 4 introspection files. Is gobject-introspection installed?",
diff --git a/tests/sample_errors/no_import_version.blp b/tests/sample_errors/no_import_version.blp
new file mode 100644
index 0000000..665ce62
--- /dev/null
+++ b/tests/sample_errors/no_import_version.blp
@@ -0,0 +1 @@
+using Gtk 
\ No newline at end of file
diff --git a/tests/sample_errors/no_import_version.err b/tests/sample_errors/no_import_version.err
new file mode 100644
index 0000000..4ee792f
--- /dev/null
+++ b/tests/sample_errors/no_import_version.err
@@ -0,0 +1 @@
+1,10,0,Expected a version number for GTK
diff --git a/tests/test_samples.py b/tests/test_samples.py
index 84cdb4f..ea6b2ea 100644
--- a/tests/test_samples.py
+++ b/tests/test_samples.py
@@ -188,6 +188,7 @@ class TestSamples(unittest.TestCase):
         self.assert_sample_error("gtk_exact_version")
         self.assert_sample_error("invalid_bool")
         self.assert_sample_error("layout_in_non_widget")
+        self.assert_sample_error("no_import_version")
         self.assert_sample_error("ns_not_imported")
         self.assert_sample_error("not_a_class")
         self.assert_sample_error("object_dne")