Doctrine\ODM\CouchDB\Mapping\MappingException::duplicateFieldMapping PHP Method

    public static function duplicateFieldMapping($className, $fieldName)
    {
        return new self("Cannot map duplicate field '" . $className . "::" . $fieldName . "'.");
    }

 protected function validateAndCompleteFieldMapping($mapping)
 {
     if (!isset($mapping['fieldName']) || !$mapping['fieldName']) {
         throw new MappingException("Mapping a property requires to specify the name.");
     }
     if (!isset($mapping['jsonName'])) {
         $mapping['jsonName'] = $mapping['fieldName'];
     }
     if (isset($this->fieldMappings[$mapping['fieldName']]) || isset($this->associationsMappings[$mapping['fieldName']])) {
         throw MappingException::duplicateFieldMapping($this->name, $mapping['fieldName']);
     }
     return $mapping;
 }