'Override filter_all() which operates on the full list
of cells...'

def filter_all(self, cells, filter_properties):

    request_spec = filter_properties.get('request_spec', {})
    image_properties = request_spec.get('image', {}).get('properties', {})
    hypervisor_version_requires = image_properties.get('hypervisor_version_requires')
    if (hypervisor_version_requires is None):
        return cells
    filtered_cells = []
    for cell in cells:
        version = cell.capabilities.get('prominent_hypervisor_version')
        if version:
            l = list(version)
            version = str(l[0])
        if ((not version) or self._matches_version(version, hypervisor_version_requires)):
            filtered_cells.append(cell)
    return filtered_cells
