def __init__(self,<EOL>functions_to_build,<EOL>build_dir,<EOL>base_dir,<EOL>manifest_path_override=None,<EOL>container_manager=None,<EOL>parallel=False,<EOL>mode=None):
self._functions_to_build = functions_to_build<EOL>self._build_dir = build_dir<EOL>self._base_dir = base_dir<EOL>self._manifest_path_override = manifest_path_override<EOL>self._container_manager = container_manager<EOL>self._parallel = parallel<EOL>self._mode = mode<EOL>
Initialize the class

Parameters
----------
functions_to_build: Iterator
    Iterator that can vend out functions available in the SAM template

build_dir : str
    Path to the directory where we will be storing built artifacts

base_dir : str
    Path to a folder. Use this folder as the root to resolve relative source code paths against

container_manager : samcli.local.docker.manager.ContainerManager
    Optional. If provided, we will attempt to build inside a Docker Container

parallel : bool
    Optional. Set to True to build each function in parallel to improve performance

mode : str
    Optional, name of the build mode to use ex: 'debug'