src/ItemCollectors/ContractCollector.php
public function singleton(string $abstract, $concrete = null, array $arguments = []): self
    {
        $this->data->singleton($abstract, $concrete, $arguments);
        return $this;
    }
public function singleton(string $abstract, $concrete = null, array $arguments = []): self
    {
        $this->data->singleton($abstract, $concrete, $arguments);
        return $this;
    }
public function singleton ( string $ abstract , $ concrete = null , array $ arguments = [ ] ) : self { $ this -> data -> singleton ( $ abstract , $ concrete , $ arguments ) ; return $ this ; }
Register a singleton binding with the container.

@param   string $abstract Class name or interface name
@param   string|callable|null $concrete
@param   array   $arguments

@return  self
Register a singleton binding with the container .