How to output the number of vertices, edges and faces given a polygon with Python? So far I have written the following code. I am super new to python

class polygon(object):
    def__init__(self, edge, face, vertex='')
        self.edge = edge
        self.face = face
        self.vertex = vertex
        self.tetrahedron = tetrahedron

a = polygon('6', '4', '4', tetrahedron)
print a.edge, a.face, a.vertex, a.tetrahedron
print a  


Also How can find the mesh module in Python? I am using spyder and I cant find it in the library.  Please help if anyone can.
You can get the active object for instance:

ob = bpy.context.object


And get its data (if it's a mesh object, the mesh datablock):

me = ob.data


Mesh element counts:

len(me.vertices)
len(me.edges)
len(me.polygons) # faces


Vertex count of a single face:

len(me.polygons[0].vertices)