Query which version(s) of the specified snap package are installed.
    Returns a list of 0 or more dictionaries.

    pkg
        The package name

def versions_installed(pkg):
    '''
    Query which version(s) of the specified snap package are installed.
    Returns a list of 0 or more dictionaries.

    pkg
        The package name
    '''

    try:
        # Try to run it, merging stderr into output
        output = subprocess.check_output([SNAP_BINARY_NAME, 'list', pkg], stderr=subprocess.STDOUT)
    except subprocess.CalledProcessError:
        return []

    lines = output.splitlines()[1:]
    ret = []
    for item in lines:
        # If fields contain spaces this will break.
        i = item.split()
        # Ignore 'Notes' field
        ret.append({
            'name':         i[0],
            'version':      i[1],
            'rev':          i[2],
            'tracking':     i[3],
            'publisher':    i[4]
            })

    return ret