'Return the repository\'s tool dependencies that are not currently installed, and may not ever have been installed.'

@property
def missing_tool_dependencies(self):

    missing_dependencies = []
    for tool_dependency in self.tool_dependencies:
        if (tool_dependency.status not in [ToolDependency.installation_status.INSTALLED]):
            missing_dependencies.append(tool_dependency)
    return missing_dependencies
