Trying to conditionally render a petition card image

attempts.haml

Code before changes (compiles and shows petition image):
```
= CommsTemplates.HamlHelpers.one_row_tr %{td: %{ align: 'left'}}, fn ->
  %img{src: "{{petition.photo_url}}", class: 'petition-centered-img-lg', style: 'border-radius: 0; margin-right: 0; margin-left: 0;'}
```

Attempt 1 (throws error):

```
- if '{{petition.photo_url}}' do
  - img_url = '{{petition.photo_url}}'
- else
  - img_url = "https://static.change.org/carousel/hands-raised.jpg"

= CommsTemplates.HamlHelpers.one_row_tr %{td: %{ align: 'left'}}, fn ->
  %img{src: img_url, class: 'petition-centered-img-lg',}
 ```
  
  Attempt 2 (Compiles but does not render photo):
  ```
  - if '{{petition.photo_url}}' do
  - img_url = '{{petition.photo_url}}'
- else
  - img_url = "https://static.change.org/carousel/hands-raised.jpg"

= CommsTemplates.HamlHelpers.one_row_tr %{td: %{ align: 'left'}}, fn ->
  %img{src: "{{img_url}}", class: 'petition-centered-img-lg'}
  ```
  
  Attempt 3 (compiles and renders photo):
  ```
= CommsTemplates.HamlHelpers.one_row_tr %{td: %{ align: 'left'}}, fn ->
 %img{src: "https://static.change.org/carousel/hands-raised.jpg", class: 'petition-centered-img-lg'}
 
 ```
 
 Attempt 4 (compiles but does not render photo): 
 ```
 -img_url = "https://static.change.org/carousel/hands-raised.jpg"

= CommsTemplates.HamlHelpers.one_row_tr %{td: %{ align: 'left'}}, fn ->
  ="{% if petition.photo_url %}"
    %img{src: "{{petition.photo_url}}", class: 'petition-centered-img-lg', style: 'border-radius: 0; margin-right: 0; margin-left: 0;'}
  ="{% else %}"
    %img{src: "{{img_url}}", class: 'petition-centered-img-lg', style: 'border-radius: 0; margin-right: 0; margin-left: 0;'}
  ="{% endif %}"
  ```

Attempt 5 (throws error):
```
-img_url = "https://static.change.org/carousel/hands-raised.jpg"

= CommsTemplates.HamlHelpers.one_row_tr %{td: %{ align: 'left'}}, fn ->
  ="{% if petition.photo_url %}"
    %img{src: "{{petition.photo_url}}", class: 'petition-centered-img-lg', style: 'border-radius: 0; margin-right: 0; margin-left: 0;'}
  ="{% else %}"
    %img{src: img_url, class: 'petition-centered-img-lg', style: 'border-radius: 0; margin-right: 0; margin-left: 0;'}
  ="{% endif %}"
  ```
  
  Attempt 6 (throws error):
  ```
  -img_url = "https://static.change.org/carousel/hands-raised.jpg"

= CommsTemplates.HamlHelpers.one_row_tr %{td: %{ align: 'left'}}, fn ->
  ="{% if petition.photo_url %}"
    %img{src: "{{petition.photo_url}}", class: 'petition-centered-img-lg', style: 'border-radius: 0; margin-right: 0; margin-left: 0;'}
  ="{% else %}"
    %img{src: {{img_url}}, class: 'petition-centered-img-lg', style: 'border-radius: 0; margin-right: 0; margin-left: 0;'}
  ="{% endif %}"
  ```