root@testvm:~# prefect server start                                                                                                                                         /usr/lib/python3/dist-packages/requests/__init__.py:91: RequestsDependencyWarning: urllib3 (1.26.3) or chardet (3.0.4) doesn't match a supported version!                     RequestsDependencyWarning)                                                                                                                                                /usr/local/lib/docker/virtualenv/local/lib/python2.7/site-packages/paramiko/transport.py:33: CryptographyDeprecationWarning: Python 2 is no longer supported by the Python core team. Support for it is now deprecated in cryptography, and will be removed in the next release.                                                                          from cryptography.hazmat.backends import default_backend                                                                                                                  ERROR: The Compose file './docker-compose.yml' is invalid because:                                                                                                          services.ui.depends_on contains an invalid type, it should be an array                                                                                                      services.towel.depends_on contains an invalid type, it should be an array                                                                                                   services.apollo.depends_on contains an invalid type, it should be an array                                                                                                  services.graphql.depends_on contains an invalid type, it should be an array                                                                                                 services.hasura.depends_on contains an invalid type, it should be an array                                                                                                  Exception caught; killing services (press ctrl-C to force)                                                                                                                  /usr/local/lib/docker/virtualenv/local/lib/python2.7/site-packages/paramiko/transport.py:33: CryptographyDeprecationWarning: Python 2 is no longer supported by the Python core team. Support for it is now deprecated in cryptography, and will be removed in the next release.                                                                          from cryptography.hazmat.backends import default_backend                                                                                                                  ERROR: The Compose file './docker-compose.yml' is invalid because:                                                                                                          services.ui.depends_on contains an invalid type, it should be an array                                                                                                      services.towel.depends_on contains an invalid type, it should be an array                                                                                                   services.apollo.depends_on contains an invalid type, it should be an array                                                                                                  services.graphql.depends_on contains an invalid type, it should be an array                                                                                                 services.hasura.depends_on contains an invalid type, it should be an array                                                                                                  Traceback (most recent call last):                                                                                                                                            File "/usr/local/lib/python3.7/dist-packages/prefect/cli/server.py", line 347, in start                                                                                       ["docker-compose", "pull"], cwd=compose_dir_path, env=env                                                                                                                 File "/usr/lib/python3.7/subprocess.py", line 347, in check_call                                                                                                              raise CalledProcessError(retcode, cmd)                                                                                                                                  subprocess.CalledProcessError: Command '['docker-compose', 'pull']' returned non-zero exit status 1.                                                                                                                                                                                                                                                    During handling of the above exception, another exception occurred:                                                                                                                                                                                                                                                                                     Traceback (most recent call last):                                                                                                                                            File "/usr/local/bin/prefect", line 10, in <module>                                                                                                                           sys.exit(cli())                                                                                                                                                           File "/usr/local/lib/python3.7/dist-packages/click/core.py", line 829, in __call__                                                                                            return self.main(*args, **kwargs)                                                                                                                                         File "/usr/local/lib/python3.7/dist-packages/click/core.py", line 782, in main                                                                                                rv = self.invoke(ctx)                                                                                                                                                     File "/usr/local/lib/python3.7/dist-packages/click/core.py", line 1259, in invoke                                                                                             return _process_result(sub_ctx.command.invoke(sub_ctx))                                                                                                                   File "/usr/local/lib/python3.7/dist-packages/click/core.py", line 1259, in invoke                                                                                             return _process_result(sub_ctx.command.invoke(sub_ctx))                                                                                                                   File "/usr/local/lib/python3.7/dist-packages/click/core.py", line 1066, in invoke                                                                                             return ctx.invoke(self.callback, **ctx.params)                                                                                                                            File "/usr/local/lib/python3.7/dist-packages/click/core.py", line 610, in invoke                                                                                              return callback(*args, **kwargs)                                                                                                                                          File "/usr/local/lib/python3.7/dist-packages/prefect/cli/server.py", line 385, in start                                                                                       ["docker-compose", "down"], cwd=compose_dir_path, env=env                                                                                                                 File "/usr/lib/python3.7/subprocess.py", line 395, in check_output                                                                                                            **kwargs).stdout                                                                                                                                                          File "/usr/lib/python3.7/subprocess.py", line 487, in run                                                                                                                     output=stdout, stderr=stderr)                                                                                                                                           subprocess.CalledProcessError: Command '['docker-compose', 'down']' returned non-zero exit status 1.