diff --git a/src/decagon_pytorch/batch.py b/src/decagon_pytorch/batch.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/decagon_pytorch/data.py b/src/decagon_pytorch/data.py
new file mode 100644
index 0000000..736f558
--- /dev/null
+++ b/src/decagon_pytorch/data.py
@@ -0,0 +1,38 @@
+class Data(object):
+    def __init__(self):
+        self.node_types = []
+        self.relation_types = []
+
+    def add_node_type(self, name):
+        self.node_types.append(name)
+
+    def add_relation(self, node_type_row, node_type_column, adjacency_matrix, name):
+        n = len(self.node_types)
+        if node_type_row >= n or node_type_column >= n:
+            raise ValueError('Node type index out of bounds, add node type first')
+        self.relation_types.append((node_type_row, node_type_column, adjacency_matrix, name))
+
+    def __repr__(self):
+        n = len(self.node_types)
+        if n == 0:
+            return 'Empty GNN Data'
+        s = ''
+        s += 'GNN Data with:\n'
+        s += '- ' + str(n) + ' node type(s):\n'
+        for nt in self.node_types:
+            s += '  - ' + nt + '\n'
+        if len(self.relation_types) == 0:
+            s += '- No relation types\n'
+            return s.strip()
+        s += '- ' + str(len(self.relation_types)) + ' relation type(s):\n'
+        for i in range(n):
+            for j in range(n):
+                rels = list(filter(lambda a: a[0] == i and a[1] == j, self.relation_types))
+                if len(rels) == 0:
+                    continue
+                # dir = '<->' if i == j else '->'
+                dir = '--'
+                s += '  - ' + self.node_types[i] + ' ' + dir + ' ' + self.node_types[j] + ':\n'
+                for r in rels:
+                    s += '    - ' + r[3] + '\n'
+        return s.strip()
diff --git a/src/decagon_pytorch/normalize.py b/src/decagon_pytorch/normalize.py
new file mode 100644
index 0000000..54ddb8e
--- /dev/null
+++ b/src/decagon_pytorch/normalize.py
@@ -0,0 +1,18 @@
+import numpy as np
+import scipy.sparse as sp
+
+
+def normalize_adjacency_matrix(self, adj):
+    adj = sp.coo_matrix(adj)
+    if adj.shape[0] == adj.shape[1]:
+        adj_ = adj + sp.eye(adj.shape[0])
+        rowsum = np.array(adj_.sum(1))
+        degree_mat_inv_sqrt = sp.diags(np.power(rowsum, -0.5).flatten())
+        adj_normalized = adj_.dot(degree_mat_inv_sqrt).transpose().dot(degree_mat_inv_sqrt).tocoo()
+    else:
+        rowsum = np.array(adj.sum(1))
+        colsum = np.array(adj.sum(0))
+        rowdegree_mat_inv = sp.diags(np.nan_to_num(np.power(rowsum, -0.5)).flatten())
+        coldegree_mat_inv = sp.diags(np.nan_to_num(np.power(colsum, -0.5)).flatten())
+        adj_normalized = rowdegree_mat_inv.dot(adj).dot(coldegree_mat_inv).tocoo()
+    return preprocessing.sparse_to_tuple(adj_normalized)
diff --git a/tests/decagon_pytorch/test_data.py b/tests/decagon_pytorch/test_data.py
new file mode 100644
index 0000000..b0c2b56
--- /dev/null
+++ b/tests/decagon_pytorch/test_data.py
@@ -0,0 +1,13 @@
+from decagon_pytorch.data import Data
+
+
+def test_data():
+    d = Data()
+    d.add_node_type('Gene')
+    d.add_node_type('Drug')
+    d.add_relation(1, 0, None, 'Target')
+    d.add_relation(0, 0, None, 'Interaction')
+    d.add_relation(1, 1, None, 'Side Effect: Nausea')
+    d.add_relation(1, 1, None, 'Side Effect: Infertility')
+    d.add_relation(1, 1, None, 'Side Effect: Death')
+    print(d)