code: def from_single(cls, meta: ProgramDescription, source: str):
          
          instance = cls(meta)
          instance.vertex_source = ShaderSource(
              VERTEX_SHADER,
              meta.path or meta.vertex_shader,
              source
          )
  
          if GEOMETRY_SHADER in source:
              instance.geometry_source = ShaderSource(
                  GEOMETRY_SHADER,
                  meta.path or meta.geometry_shader,
                  source,
              )
  
          if FRAGMENT_SHADER in source:
              instance.fragment_source = ShaderSource(
                  FRAGMENT_SHADER,
                  meta.path or meta.fragment_shader,
                  source,
              )
  
          if TESS_CONTROL_SHADER in source:
              instance.tess_control_source = ShaderSource(
                  TESS_CONTROL_SHADER,
                  meta.path or meta.tess_control_shader,
                  source,
              )
  
          if TESS_EVALUATION_SHADER in source:
              instance.tess_evaluation_source = ShaderSource(
                  TESS_EVALUATION_SHADER,
                  meta.path or meta.tess_evaluation_shader,
                  source,
              )
  
          return instance
docs: Initialize a single glsl string containing all shaders