Create a client to execute code related to a file.

def create_client_for_file(self, filename, is_cython=False):
        """Create a client to execute code related to a file."""
        # Create client
        self.create_new_client(filename=filename, is_cython=is_cython)

        # Don't increase the count of master clients
        self.master_clients -= 1

        # Rename client tab with filename
        client = self.get_current_client()
        client.allow_rename = False
        tab_text = self.disambiguate_fname(filename)
        self.rename_client_tab(client, tab_text)