Как решить эту ошибку: ПРЕДУПРЕЖДЕНИЕ: root: не удалось открыть файл '/etc/apt/sources.list'

wazir@wazir:~$ sudo software-properties-gtk [sudo] password for wazir: (process:15506): Gtk-WARNING **: Locale not supported by C library. Using the fallback 'C' locale. Cannot set locale: unsupported locale setting WARNING:root:could not open file '/etc/apt/sources.list' WARNING:root:could not open file '/etc/apt/sources.list' Traceback (most recent call last): File "/usr/bin/software-properties-gtk", line 104, in <module> app = SoftwarePropertiesGtk(datadir=options.data_dir, options=options, file=file) File "/usr/lib/python2.7/dist-packages/softwareproperties/gtk/SoftwarePropertiesGtk.py", line 89, in __init__ SoftwareProperties.__init__(self, options=options, datadir=datadir) File "/usr/lib/python2.7/dist-packages/softwareproperties/SoftwareProperties.py", line 97, in __init__ self.reload_sourceslist() File "/usr/lib/python2.7/dist-packages/softwareproperties/SoftwareProperties.py", line 585, in reload_sourceslist self.distro.get_sources(self.sourceslist) File "/usr/lib/python2.7/dist-packages/aptsources/distro.py", line 87, in get_sources raise NoDistroTemplateException("Error: could not find a " aptsources.distro.NoDistroTemplateException: Error: could not find a distribution template