code: def CheckForPresenceOf(self, reslist):
          '''This checks whether residues in reslist exist in the ATOM lines.
             It returns a list of the residues in reslist which did exist.'''
          if type(reslist) == type(""):
              reslist = [reslist]
  
          foundRes = {}
          for line in self.lines:
              resname = line[17:20]
              if line[0:4] == "ATOM":
                  if resname in reslist:
                      foundRes[resname] = True
  
          return foundRes.keys(f CheckForPresenceOf(self, reslist):
          '''This checks whether residues in reslist exist in the ATOM lines.
             It returns a list of the residues in reslist which did exist.'''
          if type(reslist) == type(""):
              reslist = [reslist]
  
          foundRes = {}
          for line in self.lines:
              resname = line[17:20]
              if line[0:4] == "ATOM":
                  if resname in reslist:
                      foundRes[resname] = True
  
          return foundRes.keys()
docs: This checks whether residues in reslist exist in the ATOM lines.
             It returns a list of the residues in reslist which did exist.