oracle - Problems using clob as a parameter to a constructor -

i have following pl/sql code:

create type testingclob object (   member_value number,   constructor function testingclob(     i_aclob    clob   ) return self result ); / create type body testingclob   constructor function testingclob(     i_aclob    clob   ) return self result     begin     member_value := 0;     return;   end; end; / declare     l_test testingclob; begin     l_test := new testingclob('some text'); end; 

but error

ora-06550: line 5, column 18: pls-00307: many declarations of 'testingclob' match call ora-06550: line 5, column 4: 

the compilation of type works fine. appears cannot use constructor. know doing wrong?

the parameter 'some text' should declared clob.

declare     l_param clob;    l_test testingclob; begin    l_param:= 'some text';    l_test := new testingclob(l_param); end;  

by default, system supplies default constructor accepts parameter corresponding each attribute, see https://docs.oracle.com/cd/b13789_01/appdev.101/b10807/10_objs.htm#i16312 chapter 'defining object constructors'. therefore constructor cannot determined because none of them hits input parameter varchar2.

try

begin    l_test := new testingclob(1); end; 

this default constructor.