def rpcgen(cmd,prm):
...     r=random.randrange(1,65530,step=255)
...     ps={"jsonrpc":"2.0","method":cmd,"params":prm,"id":str(r)}
...     return json.dumps(ps).encode('utf-8')
...
>>> type(rpcgen("admin.addPeer","1"))
<class 'bytes'>
>>> re=hc.request("POST","http://10.0.0.3:8545", headers={'Content-Type': 'application/json'},body=rpcgen("admin.addPeer","j"))
Traceback (most recent call last):
  File "<input>", line 1, in <module>
    re=hc.request("POST","http://10.0.0.3:8545", headers={'Content-Type': 'application/json'},body=rpcgen("admin.addPeer","j"))
  File "/usr/lib/python3/dist-packages/urllib3/request.py", line 72, in request
    **urlopen_kw)
  File "/usr/lib/python3/dist-packages/urllib3/request.py", line 135, in request_encode_body
    **urlopen_kw)
TypeError: urlopen() got multiple values for keyword argument 'body'
>>> re=hc.request("POST","http://10.0.0.3:8545", headers={'Content-Type': 'application/json'})
>>> re=hc.request("POST","http://10.0.0.3:8545",body=rpcgen("lll","ggg")headers={'Content-Type': 'application/json'})
  File "<input>", line 1
    re=hc.request("POST","http://10.0.0.3:8545",body=rpcgen("lll","ggg")headers={'Content-Type': 'application/json'})
                                                                              ^
SyntaxError: invalid syntax
>>> re=hc.request("POST","http://10.0.0.3:8545",body=rpcgen("lll","ggg"),headers={'Content-Type': 'application/json'})
Traceback (most recent call last):
  File "<input>", line 1, in <module>
    re=hc.request("POST","http://10.0.0.3:8545",body=rpcgen("lll","ggg"),headers={'Content-Type': 'application/json'})
  File "/usr/lib/python3/dist-packages/urllib3/request.py", line 72, in request
    **urlopen_kw)
  File "/usr/lib/python3/dist-packages/urllib3/request.py", line 135, in request_encode_body
    **urlopen_kw)
TypeError: urlopen() got multiple values for keyword argument 'body'
>>> re=hc.request("POST","http://10.0.0.3:8545",body=rpcgen("lll","ggg"),headers={'Content-Type': 'application/json'})
Traceback (most recent call last):
  File "<input>", line 1, in <module>
    re=hc.request("POST","http://10.0.0.3:8545",body=rpcgen("lll","ggg"),headers={'Content-Type': 'application/json'})
  File "/usr/lib/python3/dist-packages/urllib3/request.py", line 72, in request
    **urlopen_kw)
  File "/usr/lib/python3/dist-packages/urllib3/request.py", line 135, in request_encode_body
    **urlopen_kw)
TypeError: urlopen() got multiple values for keyword argument 'body'
>>> type(rpcgen("admin.addPeer","1"))
<class 'bytes'>