src/Schema.php
public function getMixin($mixinId)
    {
        if (isset($this->mixins[$mixinId])) {
            return $this->mixins[$mixinId];
        }

        if (isset($this->mixinsByCurie[$mixinId])) {
            return $this->mixinsByCurie[$mixinId];
        }

        throw new MixinNotDefined($this, $mixinId);
    }
public function getMixin($mixinId)
    {
        if (isset($this->mixins[$mixinId])) {
            return $this->mixins[$mixinId];
        }

        if (isset($this->mixinsByCurie[$mixinId])) {
            return $this->mixinsByCurie[$mixinId];
        }

        throw new MixinNotDefined($this, $mixinId);
    }
@param string $mixinId

@return Mixin
@throws MixinNotDefined