### Checked other resources

- [X] I added a very descriptive title to this issue.
- [X] I searched the LangChain documentation with the integrated search.
- [X] I used the GitHub search to find a similar question and didn't find it.
- [X] I am sure that this is a bug in LangChain rather than my code.
- [X] The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package).

### Example Code

I can reproduce it with this simple example:

```python
@chain
def four(input):
    return 'four'

print(four.get_graph().draw_mermaid())
```

### Error Message and Stack Trace (if applicable)

It produces this Mermaid:

```
%%{init: {'flowchart': {'curve': 'linear'}}}%%
graph TD;
        four_input:::startclass;
        Lambda_four_([Lambda(four)]):::otherclass;
        four_output:::endclass;
        four_input --> Lambda_four_;
        Lambda_four_ --> four_output;
        classDef startclass fill:#ffdfba;
        classDef endclass fill:#baffc9;
        classDef otherclass fill:#fad7de;
```

Which is invalid:

```
Error: Parse error on line 3:
...Lambda_four_([Lambda(four)]):::otherclas
-----------------------^
Expecting 'SQE', 'DOUBLECIRCLEEND', 'PE', '-)', 'STADIUMEND', 'SUBROUTINEEND', 'PIPE', 'CYLINDEREND', 'DIAMOND_STOP', 'TAGEND', 'TRAPEND', 'INVTRAPEND', 'UNICODE_TEXT', 'TEXT', 'TAGSTART', got 'PS'
```

It can be fixed by adding quotes to the node label:

```
        Lambda_four_([Lambda(four)]):::otherclass;
# should be:
        Lambda_four_(["Lambda(four)"]):::otherclass;
```

### Description

Perhaps I'm missing something, but when using the draw_mermaid() function on a chain/runnable it outputs incorrect mermaid syntax.

### System Info

```
langchain==0.2.1
```
Invalid Mermaid Syntax
This is a GitHub Issue
repo:langchain
owner:hwchase17
Title : Invalid Mermaid Syntax
Issue date:

--- start body ---
### Checked other resources

- [X] I added a very descriptive title to this issue.
- [X] I searched the LangChain documentation with the integrated search.
- [X] I used the GitHub search to find a similar question and didn't find it.
- [X] I am sure that this is a bug in LangChain rather than my code.
- [X] The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package).

### Example Code

I can reproduce it with this simple example:

```python
@chain
def four(input):
    return 'four'

print(four.get_graph().draw_mermaid())
```

### Error Message and Stack Trace (if applicable)

It produces this Mermaid:

```
%%{init: {'flowchart': {'curve': 'linear'}}}%%
graph TD;
        four_input:::startclass;
        Lambda_four_([Lambda(four)]):::otherclass;
        four_output:::endclass;
        four_input --> Lambda_four_;
        Lambda_four_ --> four_output;
        classDef startclass fill:#ffdfba;
        classDef endclass fill:#baffc9;
        classDef otherclass fill:#fad7de;
```

Which is invalid:

```
Error: Parse error on line 3:
...Lambda_four_([Lambda(four)]):::otherclas
-----------------------^
Expecting 'SQE', 'DOUBLECIRCLEEND', 'PE', '-)', 'STADIUMEND', 'SUBROUTINEEND', 'PIPE', 'CYLINDEREND', 'DIAMOND_STOP', 'TAGEND', 'TRAPEND', 'INVTRAPEND', 'UNICODE_TEXT', 'TEXT', 'TAGSTART', got 'PS'
```

It can be fixed by adding quotes to the node label:

```
        Lambda_four_([Lambda(four)]):::otherclass;
# should be:
        Lambda_four_(["Lambda(four)"]):::otherclass;
```

### Description

Perhaps I'm missing something, but when using the draw_mermaid() function on a chain/runnable it outputs incorrect mermaid syntax.

### System Info

```
langchain==0.2.1
```
--- end body ---
