The ornamental design for a generator, as shown and described.
1. Generator
2. Generator
1.1: Front
1.2: Back
1.3: Left
1.4: Right
1.5: Top
1.6: Bottom
1.7: Perspective
1.8: Perspective
1.9: Perspective
1.10: Perspective
1.11alternate perspective view; and
1.12another alternate perspective view.
Reproduction 1.1: front view of design 1; Reproduction 1.2: back view of design 1; Reproduction 1.3: left view of design 1; Reproduction 1.4: right view of design 1; Reproduction 1.5: top view of design 1; Reproduction 1.6: bottom view of design 1; Reproduction 1.7: perspective view (front, top, right side) of design 1; Reproduction 1.8: perspective view (back, bottom, left side) of design 1; Reproduction 1.9: perspective view (front, top, left side) of design 1; Reproduction 1.10: perspective view (back, bottom, right side) of design 1; Reproduction 1.11: usage state reference view of design 1; Reproduction 1.12: usage state reference view of design 1.