code: public final ListCompaniesPagedResponse listCompanies(String parent) {
      ListCompaniesRequest request = ListCompaniesRequest.newBuilder().setParent(parent).build();
      return listCompanies(request);
    }
docs: Lists all companies associated with the project.
  
  <p>Sample code:
  
  <pre><code>
  try (CompanyServiceClient companyServiceClient = CompanyServiceClient.create()) {
  TenantOrProjectName parent = TenantName.of("[PROJECT]", "[TENANT]");
  for (Company element : companyServiceClient.listCompanies(parent.toString()).iterateAll()) {
  // doThingsWith(element);
  }
  }
  </code></pre>
  
  @param parent Required.
  <p>Resource name of the tenant under which the company is created.
  <p>The format is "projects/{project_id}/tenants/{tenant_id}", for example,
  "projects/api-test-project/tenant/foo".
  <p>Tenant id is optional and the default tenant is used if unspecified, for example,
  "projects/api-test-project".
  @throws com.google.api.gax.rpc.ApiException if the remote call fails