code: def _chk_docopts(self, kws):
          
          # outfile should contain .png, .png, etc.
          outfile = kws['outfile']
          if len(kws) == 2 and os.path.basename(kws['obo']) == "go-basic.obo" and \
              kws['outfile'] == self.dflt_outfile:
              self._err("NO GO IDS SPECFIED", err=False)
          if 'obo' in outfile:
              self._err("BAD outfile({O})".format(O=outfile))
          if 'gaf' in kws and 'gene2go' in kws:
              self._err("SPECIFY ANNOTAIONS FROM ONE FILE")
          if 'gene2go' in kws:
              if 'taxid' not in kws:
                  self._err("SPECIFIY taxid WHEN READ NCBI'S gene2go FILE")
docs: Check for common user command-line errors.