function _getPath(schema, path, cleanPath) {
  if (schema.paths.hasOwnProperty(path)) {
    return schema.paths[path];
  }
  if (schema.subpaths.hasOwnProperty(cleanPath)) {
    const subpath = schema.subpaths[cleanPath];
    if (subpath === 'nested') {
      return undefined;
    }
    return subpath;
  }
  if (schema.singleNestedPaths.hasOwnProperty(cleanPath) && typeof schema.singleNestedPaths[cleanPath] === 'object') {
    const singleNestedPath = schema.singleNestedPaths[cleanPath];
    if (singleNestedPath === 'nested') {
      return undefined;
    }
    return singleNestedPath;
  }

  return null;
}
Gets/sets schema paths.

Sets a path (if arity 2)
Gets a path (if arity 1)

#### Example:

    schema.path('name') // returns a SchemaType
    schema.path('name', Number) // changes the schemaType of `name` to Number

@param {String} path The name of the Path to get / set
@param {Object} [obj] The Type to set the path to, if provided the path will be SET, otherwise the path will be GET
@api public