class_docstr: A collection of protobufs dynamically constructed by descriptor protos.
class_docstr_tok: ["A","collection","of","protobufs","dynamically","constructed","by","descriptor","protos","."]
docstr: Initializes a Pool of proto buffs.
  
  The descriptor_db argument to the constructor is provided to allow
  specialized file descriptor proto lookup code to be triggered on demand. An
  example would be an implementation which will read and compile a file
  specified in a call to FindFileByName() and not require the call to Add()
  at all. Results from this database will be cached internally here as well.
  
  Args:
    descriptor_db: A secondary source of file descriptors.
code: def __init__(self, descriptor_db=None):
      """Initializes a Pool of proto buffs.
  
      The descriptor_db argument to the constructor is provided to allow
      specialized file descriptor proto lookup code to be triggered on demand. An
      example would be an implementation which will read and compile a file
      specified in a call to FindFileByName() and not require the call to Add()
      at all. Results from this database will be cached internally here as well.
  
      Args:
        descriptor_db: A secondary source of file descriptors.
      """
  
      self._internal_db = descriptor_database.DescriptorDatabase()
      self._descriptor_db = descriptor_db
      self._descriptors = {}
      self._enum_descriptors = {}
      self._service_descriptors = {}
      self._file_descriptors = {}
      self._toplevel_extensions = {}
      # TODO(jieluo): Remove _file_desc_by_toplevel_extension after
      # maybe year 2020 for compatibility issue (with 3.4.1 only).
      self._file_desc_by_toplevel_extension = {}
      self._top_enum_values = {}
      # We store extensions in two two-level mappings: The first key is the
      # descriptor of the message being extended, the second key is the extension
      # full name or its tag number.
      self._extensions_by_name = collections.defaultdict(dict)
      self._extensions_by_number = collections.defaultdict(dict)
  
imports: import collections
  import warnings
  from google.protobuf import descriptor
  from google.protobuf import descriptor_database
  from google.protobuf import text_encoding
label_desc: Use image node_id 1 to create a new DescriptorPool object from inherited base classes: object with example: obj = DescriptorPool(descriptor_db)