```ruby
name :bsa
require_helpers :get_field_as_float

execute do
  weight = get_field_as_float :weight_in_kg
  height = get_field_as_float :height_in_m

  raise FieldError.new('weight', 'weight must be greater than zero') if weight <= 0
  raise FieldError.new('height', 'height must be greater than zero') if height <= 0

  {
    value: ((weight * (height * 100)) / 3600) ** 0.5,
    units: 'm^2'
  }
end
```

Remove redundant field name from error
user
```ruby
name :bsa
require_helpers :get_field_as_float

execute do
  weight = get_field_as_float :weight_in_kg
  height = get_field_as_float :height_in_m

  raise FieldError.new('weight', 'must be greater than zero') if weight <= 0
  raise FieldError.new('height', 'must be greater than zero') if height <= 0

  {
    value: ((weight * (height * 100)) / 3600) ** 0.5,
    units: 'm^2'
  }
end
```
assistant