'Conditional data loader will download and extract zip files if not found locally.'

def load_data(self):

    self.zip_paths = {}
    for phase in self.filemap:
        zn = self.gen_zipname(phase)
        size = self.filemap[phase]
        self.zip_paths[phase] = self.load_zip(zn, size)
    return self.zip_paths
