diff --git a/moto/ec2/utils.py b/moto/ec2/utils.py
index 74fe3d27b..61d22d8b2 100644
--- a/moto/ec2/utils.py
+++ b/moto/ec2/utils.py
@@ -196,22 +196,6 @@ def split_route_id(route_id):
     return values[0], values[1]
 
 
-def tags_from_query_string(querystring_dict):
-    prefix = "Tag"
-    suffix = "Key"
-    response_values = {}
-    for key, value in querystring_dict.items():
-        if key.startswith(prefix) and key.endswith(suffix):
-            tag_index = key.replace(prefix + ".", "").replace("." + suffix, "")
-            tag_key = querystring_dict.get("Tag.{0}.Key".format(tag_index))[0]
-            tag_value_key = "Tag.{0}.Value".format(tag_index)
-            if tag_value_key in querystring_dict:
-                response_values[tag_key] = querystring_dict.get(tag_value_key)[0]
-            else:
-                response_values[tag_key] = None
-    return response_values
-
-
 def dhcp_configuration_from_querystring(querystring, option="DhcpConfiguration"):
     """
     turn:
diff --git a/moto/emr/responses.py b/moto/emr/responses.py
index 3708db0ed..d2b234ced 100644
--- a/moto/emr/responses.py
+++ b/moto/emr/responses.py
@@ -10,9 +10,10 @@ from six.moves.urllib.parse import urlparse
 from moto.core.responses import AWSServiceSpec
 from moto.core.responses import BaseResponse
 from moto.core.responses import xml_to_json_response
+from moto.core.utils import tags_from_query_string
 from .exceptions import EmrError
 from .models import emr_backends
-from .utils import steps_from_query_string, tags_from_query_string
+from .utils import steps_from_query_string
 
 
 def generate_boto3_response(operation):
@@ -91,7 +92,7 @@ class ElasticMapReduceResponse(BaseResponse):
     @generate_boto3_response("AddTags")
     def add_tags(self):
         cluster_id = self._get_param("ResourceId")
-        tags = tags_from_query_string(self.querystring)
+        tags = tags_from_query_string(self.querystring, prefix="Tags")
         self.backend.add_tags(cluster_id, tags)
         template = self.response_template(ADD_TAGS_TEMPLATE)
         return template.render()
diff --git a/moto/emr/utils.py b/moto/emr/utils.py
index 0f75995b8..fb33214c8 100644
--- a/moto/emr/utils.py
+++ b/moto/emr/utils.py
@@ -22,22 +22,6 @@ def random_instance_group_id(size=13):
     return "i-{0}".format(random_id())
 
 
-def tags_from_query_string(querystring_dict):
-    prefix = "Tags"
-    suffix = "Key"
-    response_values = {}
-    for key, value in querystring_dict.items():
-        if key.startswith(prefix) and key.endswith(suffix):
-            tag_index = key.replace(prefix + ".", "").replace("." + suffix, "")
-            tag_key = querystring_dict.get("Tags.{0}.Key".format(tag_index))[0]
-            tag_value_key = "Tags.{0}.Value".format(tag_index)
-            if tag_value_key in querystring_dict:
-                response_values[tag_key] = querystring_dict.get(tag_value_key)[0]
-            else:
-                response_values[tag_key] = None
-    return response_values
-
-
 def steps_from_query_string(querystring_dict):
     steps = []
     for step in querystring_dict: