lib/Elastica/Type/Mapping.php
public function setParam(string $key, $value): Mapping
    {
        $this->_mapping[$key] = $value;

        return $this;
    }
public function setParam(string $key, $value): Mapping
    {
        $this->_mapping[$key] = $value;

        return $this;
    }
public function setParam ( string $ key , $ value ) : Mapping { $ this -> _mapping [ $ key ] = $ value ; return $ this ; }
Sets raw parameters.

Possible options:
_uid
_id
_type
_source
_analyzer
_boost
_routing
_index
_size
properties

@param string $key   Key name
@param mixed  $value Key value

@return $this
Sets raw parameters .