In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Treatment with L - DOPA + benserazide ( 12 weeks ) resulted in less severe dyskinesias in CB1 KO than in WT mice .
### Output Text:
Treatment with <span class="chemical">L - DOPA + benserazide</span> ( 12 weeks ) resulted in less severe dyskinesias in CB1 KO than in WT mice . 