Merge pull request #2507 from hugovk/replace-deprecated

Replace deprecated inspect.formatargspec with inspect.signature

botocore/docs/method.py

@@ -101,13 +101,7 @@ def document_custom_signature(
     :param exclude: The names of the parameters to exclude from
         documentation.
     """
-    argspec = inspect.getfullargspec(method)
-    signature_params = inspect.formatargspec(
-        args=argspec.args[1:],
-        varargs=argspec.varargs,
-        varkw=argspec.varkw,
-        defaults=argspec.defaults,
-    )
+    signature_params = str(inspect.signature(method))
     signature_params = signature_params.lstrip('(')
     signature_params = signature_params.rstrip(')')
     section.style.start_sphinx_py_method(name, signature_params)