Copy shape key values to another mesh in Blender

copy-shapekey-values.py

srcMesh = bpy.data.meshes['Mesh.017']
tgtMesh = bpy.data.meshes['Mesh.002']
# Usage: 
# Copy script to Notepad (or similar) so you can edit the names above
#     The mesh names are what appear at the top of the Properties window when you have the green mesh data tab selected (ie the page where you can see shape keys)
# At the top select 'Scripting' tab (from the row that has 'Layout', 'Modelling', 'UV Editing', 'Shading', etc)
# In the Python console window (the window that has green text 'PYTHON INTERACTIVE CONSOLE') paste the entire code in with your edited names


def keysToDict(keys):
    return { key.name: key for key in keys.key_blocks }


srcKeys = keysToDict(srcMesh.shape_keys)
tgtKeys = keysToDict(tgtMesh.shape_keys)
for i in srcKeys:
    if i in tgtKeys:
        tgtKeys[i].value = srcKeys[i].value
    else:
        print("Key " + i + " does not exist in target")