code: def pop_header(self, hkey, ignore_error=False):
          
  
          # try the integer approach first to allow negative values
          if type(hkey) is not str:
              try:    
                  return self.headers.pop(self.hkeys.pop(hkey))
              except: 
                  if not ignore_error:
                      print("ERROR: pop_header() could not find hkey "+str(hkey))
                  return None
          else:
              
              try:
                  # find the key integer and pop it
                  hkey = self.hkeys.index(hkey)
      
                  # pop it!
                  return self.headers.pop(self.hkeys.pop(hkey))
  
              except:
                  if not ignore_error:
                      print("ERROR: pop_header() could not find hkey "+str(hkey))
                  return
docs: This will remove and return the specified header value.
  
          Parameters
          ----------
          hkey
              Header key you wish to pop. 
              You can specify either a key string or an index.
          ignore_error=False
              Whether to quietly ignore any errors (i.e., hkey not found).