We claim the ornamental design for a collapsible bag, as shown and described.
FIG. 1 is a top, front, left side perspective view of a collapsible bag. The broken lines depicting an outline of a hook represent environmental matter and form no part of the claimed design. Additionally, the uniformly short dashed lines depicting a lower portion of the bag form no part of the claimed design.
FIG. 2 is a front elevation view of a collapsible bag, the rear elevation view being a mirror image. The uniformly short dashed lines depicting a lower portion of the bag form no part of the claimed design.
FIG. 3 is a left side elevation view of a collapsible bag, the right side elevation view being a mirror image. The uniformly short dashed lines depicting a lower portion of the bag form no part of the claimed design.
FIG. 4 is a top plan view. The uniformly short dashed lines depicting a lower surface of the bag form no part of the claimed design; and,
FIG. 5 is a bottom plan view of a collapsible bag. The uniformly short dashed lines depicting a lower surface of the bag form no part of the claimed design.
The dominant features of my design reside in handles, a bottom portion, and a hinge to be used in combination with a collapsible bag.