The following error was observed in "openerp/addons/base/ir/ir_model.py", in _get_id. The error seen was raised using:

raise ValueError('No such external ID currently defined in the system: %s.%s' % (module, xml_id))

[Error]

"ValueError: No such external ID currently defined in the system: module_name.xml_id"

Note: module_name and xml_id are placeholders for the actual error. module_name is actually the name of the custom module that I am trying to create.

What does external ID denote? How could I solve this error?