Fix contract funnction method detection

apps/ethereum_jsonrpc/lib/ethereum_jsonrpc/contract.ex

@@ -32,14 +32,21 @@ defmodule EthereumJSONRPC.Contract do
       abi
       |> ABI.parse_specification()
 
-    functions = Enum.into(parsed_abi, %{}, &{&1.function, &1})
+    functions = Enum.into(parsed_abi, %{}, &{&1.method_id, &1})
 
     requests_with_index = Enum.with_index(requests)
 
+    [{%{function_name: function_name}, _}] = requests_with_index
+
     indexed_responses =
       requests_with_index
       |> Enum.map(fn {%{contract_address: contract_address, function_name: function_name, args: args} = request, index} ->
-        functions[function_name]
+        {_, function} =
+          Enum.find(functions, fn {method_id, func} ->
+            func.function == function_name && Enum.count(func.input_names) == Enum.count(args)
+          end)
+
+        function
         |> Encoder.encode_function_call(args)
         |> eth_call_request(contract_address, index, Map.get(request, :block_number), Map.get(request, :from))
       end)