git source from documentation does not work

[AndreyMlashkin]

https://docs.conan.io/en/latest/developing_packages/package_dev_flow.html

how to reproduce:

cd ... /conan-center-index/recipes/zlib/all execute command from docs: conan source . --source-folder=tmp/source

got an error: conanfile.py (zlib/None): Configuring sources in /home/andrei/sources/conan-center-index/recipes/zlib/all/tmp/source conanfile.py (zlib/None): Executing exports to: /home/andrei/sources/conan-center-index/recipes/zlib/all/tmp/source conanfile.py (zlib/None) exports: File 'conandata.yml' found. Exporting it... conanfile.py (zlib/None) exports: Copied 1 '.yml' file: conandata.yml conanfile.py (zlib/None): Calling export_sources() conanfile.py (zlib/None) export_sources() method: Copied 1 '.txt' file: CMakeLists.txt ERROR: conanfile.py (zlib/None): Error in source() method, line 57 tools.get(**self.conan_data["sources"][self.version], KeyError: None