`<mdm:sources> validation errors`

These validation errors for Create Model and Update Model requests are specific to <mdm:sources>:

<mdm:source> has an invalid type attribute value. The valid values are Accept, Contribute, and Both. Error message:
```
<mdm:error>Invalid source type</mdm:error>
```
<mdm:source> has a type attribute value that is not a valid URL. Error message:
```
<mdm:error>Invalid entity ID URL</mdm:error>
```
<mdm:source> does not specify all required properties. Error message:
```
<mdm:error>Missing required properties for source</mdm:error>
```
<mdm:source> has an id attribute value that is the same as that of another such element. Sample error message:
```
<mdm:error>Source NS is a duplicate</mdm:error>
```
<mdm:sourceRankings> is erroneously present in <mdm:sources> because <mdm:sources> has only one child <mdm:source> element. Error message:
```
<mdm:error>Source ranking is not applicable to a single source</mdm:error>
```
<mdm:sourceRanking> has a missing or empty child <mdm:uniqueId> element. Sample error message:
```
<mdm:error>Missing CITY in source ranking</mdm:error>
```
<mdm:sourceRanking> has a child <mdm:sourceId> element containing an ID that does not correspond to the id attribute value of any <mdm:source> element. Sample error message:
```
<mdm:error>Source with ID XX does not exist</mdm:error>
```
<mdm:sourceRanking> has multiple child <mdm:sourceId> elements with the same rank attribute value. Sample error message:
```
<mdm:error>Multiple sources have rank value 1</mdm:error>
```
<mdm:sourceRanking> has multiple child <mdm:sourceId> elements with the same element content. Sample error message:
```
<mdm:error>Source NS is ranked multiple times for field</mdm:error>
```
<mdm:sourceRanking> does not have child <mdm:sourceId> elements for each child <mdm:source> element of <mdm:sources>. Sample error message:
```
<mdm:error>All sources are not ranked for field CITY</mdm:error>
```
Multiple <mdm:source> elements have a default attribute value of true. Error message:
```
<mdm:error>Multiple default sources are designated</mdm:error>
```
<mdm:source> has a default attribute value of true and a type attribute value of Accept. Error message:
```
<mdm:error>Source of type Accept should not be the default source</mdm:error>
```
<mdm:source> with a type attribute value of Accept erroneously has its child <mdm:inbound> element populated. Error message:
```
<mdm:error>Inbound configuration does not apply to source type Accept</mdm:error>
```
<mdm:updateApprovalFields> is erroneeously populated because <mdm:updateApproval> has a child <mdm:businessRule> element. Error message:
```
<mdm:error>Individual field approval is not applicable because approval is required for all updates</mdm:error>
```
<mdm:excludedFields> has a child <mdm:excludedField> element with a uniqueID attribute value that is not the uniqueId attribute value of any <mdm:field> element. Sample error message:
```
<mdm:error>Excluded field CITY does not exist in the model</mdm:error>
```
<mdm:updateApprovalFields> has a child <mdm:updateApprovalField> element with a uniqueId attribute value that is not the uniqueId attribute value of any <mdm:field> element. Sample error message:
```
<mdm:error>Update field CITY does not exist in the model</mdm:error>
```
<mdm:source> with a type attribute value of Contribute erroneously has its child <mdm:outbound> element populated. Error message:
```
<mdm:error>Outbound configuration does not apply to source type Contribute</mdm:error>
```
<mdm:channelUpdatesFields> does not contain either All or Creates. Error message:
```
<mdm:error>Invalid channel update scope</mdm:error>
```
<mdm:sendFilter> has an invalid scope attribute value. The valid values are All and Creates. Sample error message:
```
<mdm:error>Invalid channel update filter scope for source ID NS</mdm:error>
```
<mdm:tag> has a name attribute value that is not the name attribute value of a child <mdm:tag> element of the <mdm:tags> element that is a child of the model’s root element. Error message:
```
<mdm:error>A tag specified for restricting propagation of update requests does not exist in the model</mdm:error>
```
<mdm:tags> is present but it either does not have any child <mdm:tag> elements or any such <mdm:tag> elements are empty. Error message:
```
<mdm:error>Tags are not selected for restricting propagation of update requests</mdm:error>
```