diff --git a/.python-version b/.python-version
new file mode 100644
index 0000000..cac7314
--- /dev/null
+++ b/.python-version
@@ -0,0 +1 @@
+mappings-3.7.2
diff --git a/.travis.yml b/.travis.yml
index 161840a..518cb59 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,4 @@
-dist: trusty
+dist: xenial
 services:
   - postgresql
 addons:
@@ -6,7 +6,7 @@ addons:
 language: python
 cache: pip
 python:
-  - '2.7'
+  - '3.7'
 install:
   - pip install -r requirements.txt
   - pip install coveralls
diff --git a/README.rst b/README.rst
index 281a7f3..767ca65 100644
--- a/README.rst
+++ b/README.rst
@@ -3,6 +3,16 @@
 sqlalchemy-mappings
 ===================
 
+Running
+-------
+
+This project uses Python 3.7 installed using the Pyenv tool.
+
+Testing
+-------
+
+Tests are run using pytest.
+
 
 .. |Build Status| image:: https://travis-ci.org/multiplechoice/sqlalchemy-mappings.svg?branch=master
   :target: https://travis-ci.org/multiplechoice/sqlalchemy-mappings
diff --git a/mappings/__init__.py b/mappings/__init__.py
index 9d4c595..f7d350b 100644
--- a/mappings/__init__.py
+++ b/mappings/__init__.py
@@ -82,7 +82,7 @@ def spider(self):
         we get a None instead.
 
         Returns:
-            basestring or None: the name of the spider
+            string or None: the name of the spider
 
         """
         if self.data is None or 'spider' not in self.data:
diff --git a/requirements.txt b/requirements.txt
index 58db4a8..2ddef77 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
 python-dateutil==2.8.0
 psycopg2==2.7.7
-SQLAlchemy==1.2.18
-pytest==4.3.0
+SQLAlchemy==1.3.1
+pytest==4.4.0
 pytest-cov==2.6.1
\ No newline at end of file
diff --git a/tests/test_hybrid_expressions.py b/tests/test_hybrid_expressions.py
index 5a2ebc2..e45976e 100644
--- a/tests/test_hybrid_expressions.py
+++ b/tests/test_hybrid_expressions.py
@@ -63,13 +63,13 @@ def test_find_by_spider():
 def test_as_dict():
     with session_scope(FARAH) as session:
         job = session.query(ScrapedJob).filter(ScrapedJob.spider == 'tarantula').one()
-        for key, value in example_data[0].iteritems():
+        for key, value in example_data[0].items():
             assert key in job.as_dict()
             assert job.as_dict()[key] == value
 
         for key in ('created_at', 'last_modified', 'id'):
             assert key in job.as_dict()
-            assert isinstance(job.as_dict()[key], basestring)
+            assert isinstance(job.as_dict()[key], str)
 
 
 def test_date_of_posting():