hydrachain/examples/native/fungible/fungible_contract.py
def transferFrom(ctx, _from='address', _to='address', _value='uint256', returns=STATUS):
        """ Standardized Contract API:
        function transferFrom(address _from, address _to, uint256 _value) returns (bool success)
        """
        auth = ctx.allowances[_from][ctx.msg_sender]
        if ctx.accounts[_from] >= _value and auth >= _value:
            ctx.allowances[_from][ctx.msg_sender] -= _value
            ctx.accounts[_from] -= _value
            ctx.accounts[_to] += _value
            ctx.Transfer(_from, _to, _value)
            return OK
        else:
            return INSUFFICIENTFUNDS
def transferFrom(ctx, _from='address', _to='address', _value='uint256', returns=STATUS):
        """ Standardized Contract API:
        function transferFrom(address _from, address _to, uint256 _value) returns (bool success)
        """
        auth = ctx.allowances[_from][ctx.msg_sender]
        if ctx.accounts[_from] >= _value and auth >= _value:
            ctx.allowances[_from][ctx.msg_sender] -= _value
            ctx.accounts[_from] -= _value
            ctx.accounts[_to] += _value
            ctx.Transfer(_from, _to, _value)
            return OK
        else:
            return INSUFFICIENTFUNDS
Standardized Contract API:
        function transferFrom(address _from, address _to, uint256 _value) returns (bool success)