code: def get_evidence(assay):
      
      kin = get_kinetics(assay)
      source_id = assay.get('assay_chembl_id')
      if not kin:
          return None
      annotations = {'kinetics': kin}
      chembl_doc_id = str(assay.get('document_chembl_id'))
      pmid = get_pmid(chembl_doc_id)
      ev = Evidence(source_api='chembl', pmid=pmid, source_id=source_id,
                    annotations=annotations)
      return ev
docs: Given an activity, return an INDRA Evidence object.
  
      Parameters
      ----------
      assay : dict
          an activity from the activities list returned by a query to the API
  
      Returns
      -------
      ev : :py:class:`Evidence`
          an :py:class:`Evidence` object containing the kinetics of the