diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java
index cb829433f5d..3ce9fd71d20 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java
@@ -160,7 +160,7 @@ public class PythonClientCodegen extends DefaultCodegen implements CodegenConfig
         cliOptions.add(new CliOption(CodegenConstants.HIDE_GENERATION_TIMESTAMP, CodegenConstants.HIDE_GENERATION_TIMESTAMP_DESC)
                 .defaultValue(Boolean.TRUE.toString()));
         cliOptions.add(new CliOption(CodegenConstants.SOURCECODEONLY_GENERATION, CodegenConstants.SOURCECODEONLY_GENERATION_DESC)
-            .defaultValue(Boolean.FALSE.toString()));
+                .defaultValue(Boolean.FALSE.toString()));
 
         supportedLibraries.put("urllib3", "urllib3-based client");
         supportedLibraries.put("asyncio", "Asyncio-based client (python 3.5+)");
@@ -224,7 +224,7 @@ public class PythonClientCodegen extends DefaultCodegen implements CodegenConfig
             setPackageUrl((String) additionalProperties.get(PACKAGE_URL));
         }
 
-        String readmePath ="README.md";
+        String readmePath = "README.md";
         String readmeTemplate = "README.mustache";
         if (generateSourceCodeOnly) {
             readmePath = packageName + "_" + readmePath;
@@ -232,7 +232,7 @@ public class PythonClientCodegen extends DefaultCodegen implements CodegenConfig
         }
         supportingFiles.add(new SupportingFile(readmeTemplate, "", readmePath));
 
-        if (!generateSourceCodeOnly){
+        if (!generateSourceCodeOnly) {
             supportingFiles.add(new SupportingFile("tox.mustache", "", "tox.ini"));
             supportingFiles.add(new SupportingFile("test-requirements.mustache", "", "test-requirements.txt"));
             supportingFiles.add(new SupportingFile("requirements.mustache", "", "requirements.txt"));
@@ -552,6 +552,12 @@ public class PythonClientCodegen extends DefaultCodegen implements CodegenConfig
             operationId = "call_" + operationId;
         }
 
+        // model name starts with a number
+        if (operationId.matches("^\\d.*")) {
+            LOGGER.warn(operationId + " (starting with a number) cannot be used as method name. Renamed to " + underscore(sanitizeName("call_" + operationId)));
+            operationId = "call_" + operationId;
+        }
+
         return underscore(sanitizeName(operationId));
     }
 
diff --git a/samples/client/petstore/python/.openapi-generator/VERSION b/samples/client/petstore/python/.openapi-generator/VERSION
index dde25ef08e8..4395ff59232 100644
--- a/samples/client/petstore/python/.openapi-generator/VERSION
+++ b/samples/client/petstore/python/.openapi-generator/VERSION
@@ -1 +1 @@
-3.1.1-SNAPSHOT
\ No newline at end of file
+3.2.0-SNAPSHOT
\ No newline at end of file