None value returned for sql_table_names from API

[PatKearns]

Hi there,

We are pulling data from the Looker API and typically pull:

Models, then Explores.

I noticed today, when trying to get the `sql_table_name` from the joins (LookmlModelExploreJoins), that all the `sql_table_name`s are ‘None’.  

Example output:

 OrderedDict([('dependent_fields', ['dw_owl.customer_id', 'customer.id']),
              ('fields', None),
              ('foreign_key', None),
              ('from', None),
              ('outer_only', None),
              ('relationship', 'one_to_one'),
              ('required_joins', None),
              ('sql_foreign_key', None),
              ('sql_on', '${dw_owl.customer_id} = ${customer.id} '),
              ('sql_table_name', None),
              ('type', None),
              ('view_label', None),
              ('name', 'customer')]),
 OrderedDict([('dependent_fields',
               ['customer.email', 'customer_dimension.email']),
              ('fields', None),
              ('foreign_key', None),
              ('from', None),
              ('outer_only', None),
              ('relationship', 'one_to_one'),
              ('required_joins', None),
              ('sql_foreign_key', None),
              ('sql_on', '${customer.email} = ${customer_dimension.email} '),
              ('sql_table_name', None),
              ('type', 'left_outer'),
              ('view_label', 'Customer'),
              ('name', 'customer_dimension')]),
 OrderedDict([('dependent_fields',
               ['customer.email', 'dim_customers.customer_email']),
              ('fields', None),
              ('foreign_key', None),
              ('from', None),
              ('outer_only', None),
              ('relationship', 'many_to_one'),
              ('required_joins', None),
              ('sql_foreign_key', None),
              ('sql_on',
               '${customer.email} = ${dim_customers.customer_email} '),
              ('sql_table_name', None),
              ('type', 'left_outer'),
              ('view_label', 'Customers (New)'),
              ('name', 'dim_customers')])]

Any help to fix that or another way to get all View sql_table_names would be greatly appreciated.