Python generator for searching if a package is installed on an Ubuntu system

is_package_installed.py

import apt_pkg

def packages():                                                                                                                 
    """ Generator that returns all packages found on system                                                                         
    """                                                                                                                             
    apt_pkg.init_config()                                                                                                           
    apt_pkg.init_system()                                                                                                           
    package_cache = apt_pkg.Cache()                                                                                                 
    for package in package_cache.packages:                                                                                          
        if package.current_state is apt_pkg.CURSTATE_INSTALLED:                                                                     
            yield package.name
            
def is_installed(package):                                                                                                    
    """ Checks if package is installed                                                                                              
    """                                                                                                                             
    return any(package in x for x in packages())