copies entire Header class in chained_requests test script

tests/chained_requests.py

@@ -1,6 +1,15 @@
 import os, json, requests
 from getpass import getpass
-from classes import Header
+
+class Header:
+    '''
+    Class to standardize the format of the headers of our http requests.
+    '''
+    def __init__(self, apikey=""):
+        '''Init method, apikey suggested but not required (empty by default).'''
+        self.auth = {"Authorization" : apikey}
+        self.content = {"Content-Type" : "application/json"}
+        self.dump = {**self.auth, **self.content}
 
 def get_entry_from_elabid(elabid, entryType="items"):
     '''