class_docstr: Represent a GCS Object, including all its revisions.
class_docstr_tok: ["Represent","a","GCS","Object",",","including","all","its","revisions","."]
docstr: Verify that the preconditions in request are met.
  
  :param request:flask.Request the http request.
  :param if_generation_match:str the name of the generation match
      parameter name, typically 'ifGenerationMatch', but sometimes
      'ifSourceGenerationMatch'.
  :param if_generation_not_match:str the name of the generation not-match
      parameter name, typically 'ifGenerationNotMatch', but sometimes
      'ifSourceGenerationNotMatch'.
  :param if_metageneration_match:str the name of the metageneration match
      parameter name, typically 'ifMetagenerationMatch', but sometimes
      'ifSourceMetagenerationMatch'.
  :param if_metageneration_not_match:str the name of the metageneration
      not-match parameter name, typically 'ifMetagenerationNotMatch', but
      sometimes 'ifSourceMetagenerationNotMatch'.
  :rtype:NoneType
docstr_tok: ["Verify","that","the","preconditions","in","request","are","met",".",":","param","request",":","flask.Request","the","http","request",".",":","param","if_generation_match",":","str","the","name","of","the","generation","match","parameter","name",",","typically","'ifGenerationMatch","'",",","but","sometimes","'ifSourceGenerationMatch","'",".",":","param","if_generation_not_match",":","str","the","name","of","the","generation","not-match","parameter","name",",","typically","'ifGenerationNotMatch","'",",","but","sometimes","'ifSourceGenerationNotMatch","'",".",":","param","if_metageneration_match",":","str","the","name","of","the","metageneration","match","parameter","name",",","typically","'ifMetagenerationMatch","'",",","but","sometimes","'ifSourceMetagenerationMatch","'",".",":","param","if_metageneration_not_match",":","str","the","name","of","the","metageneration","not-match","parameter","name",",","typically","'ifMetagenerationNotMatch","'",",","but","sometimes","'ifSourceMetagenerationNotMatch","'",".",":","rtype",":","NoneType"]
code: def check_preconditions(
      self,
      request,
      if_generation_match="ifGenerationMatch",
      if_generation_not_match="ifGenerationNotMatch",
      if_metageneration_match="ifMetagenerationMatch",
      if_metageneration_not_match="ifMetagenerationNotMatch",
  ):
      """Verify that the preconditions in request are met.
  
      :param request:flask.Request the http request.
      :param if_generation_match:str the name of the generation match
          parameter name, typically 'ifGenerationMatch', but sometimes
          'ifSourceGenerationMatch'.
      :param if_generation_not_match:str the name of the generation not-match
          parameter name, typically 'ifGenerationNotMatch', but sometimes
          'ifSourceGenerationNotMatch'.
      :param if_metageneration_match:str the name of the metageneration match
          parameter name, typically 'ifMetagenerationMatch', but sometimes
          'ifSourceMetagenerationMatch'.
      :param if_metageneration_not_match:str the name of the metageneration
          not-match parameter name, typically 'ifMetagenerationNotMatch', but
          sometimes 'ifSourceMetagenerationNotMatch'.
      :rtype:NoneType
      """
      generation_match = request.args.get(if_generation_match)
      generation_not_match = request.args.get(if_generation_not_match)
      metageneration_match = request.args.get(if_metageneration_match)
      metageneration_not_match = request.args.get(
          if_metageneration_not_match
      )
      self.check_preconditions_by_value(
          generation_match,
          generation_not_match,
          metageneration_match,
          metageneration_not_match,
      )
  
imports: import base64
  import crc32c
  import error_response
  import hashlib
  import json
  import struct
  import testbench_utils
  import time
label_desc: Use image node_id 8 for calling the GcsObject obj's underlying member method code with example usage: obj.check_preconditions(request, if_generation_match, if_generation_not_match, if_metageneration_match, if_metageneration_not_match) without return types