add oneOf lookup option in python client generator (#16154)

Author: wing328

docs/generators/python.md

@@ -31,6 +31,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |packageVersion|python package version.| |1.0.0|
 |projectName|python project name in setup.py (e.g. petstore-api).| |null|
 |recursionLimit|Set the recursion limit. If not set, use the system default value.| |null|
+|useOneOfDiscriminatorLookup|Use the discriminator's mapping in oneOf to speed up the model lookup. IMPORTANT: Validation (e.g. one and only one match in oneOf's schemas) will be skipped.| |false|
 
 ## IMPORT MAPPING
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java

@@ -180,6 +180,7 @@ public PythonClientCodegen() {
                 .defaultValue("%Y-%m-%dT%H:%M:%S%z"));
         cliOptions.add(new CliOption(DATE_FORMAT, "date format for query parameters")
                 .defaultValue("%Y-%m-%d"));
+        cliOptions.add(new CliOption(CodegenConstants.USE_ONEOF_DISCRIMINATOR_LOOKUP, CodegenConstants.USE_ONEOF_DISCRIMINATOR_LOOKUP_DESC).defaultValue("false"));
 
         supportedLibraries.put("urllib3", "urllib3-based client");
         supportedLibraries.put("asyncio", "asyncio-based client");