[Bug-Candidate]: get_dependencies bug

### Describe the issue:

test.sol:
```
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.12;
contract Contract {
uint256 var_amount;

function direct_returns(uint256 amount) internal returns (uint256) {
uint256 _amount = var_amount + amount;
return _amount;
}

function indirect_returns(uint256 amount)
internal
returns (uint256 _amount)
{
_amount = var_amount + amount;
}

function test() external {
uint256 a = direct_returns(10);
uint256 b = indirect_returns(10);
}
}
```

test.py:
```
direct_returns_function:Function
indirect_returns_function:Function
test_function:Function
a_variable:Variable
b_variable:Variable

#contract is test.sol:Contract
for function in contract.functions:
if function.name=="direct_returns":
direct_returns_function = function
elif function.name=="indirect_returns":
indirect_returns_function = function
elif function.name=="test":
test_function = function

for vari in test_function.variables_as_dict.values():
if vari.name=="a":
a_variable = vari
elif vari.name=="b":
b_variable = vari

print([vari.name for vari in get_dependencies(a_variable,contract)])
print([vari.name for vari in get_dependencies(b_variable,contract)])
```

get result:
```
['TMP_2', 'TMP_0', 'amount', '_amount', 'var_amount']
['TMP_3']
```
I was expecting the same result (same result length), but here it is different

### Code example to reproduce the issue:

``

### Version:

0.9.1

### Relevant log output:

_No response_