whole_func_string: function getDisplayName(path) {
      const componentName = getName(path)
      const filename = getFileName(file)
      if (filename) {
        if (filename === componentName) {
          return componentName
        }
        return componentName ? `${filename}__${componentName}` : filename
      } else {
        return componentName
      }
    }
func_code_string: function getDisplayName(path) {
      const componentName = getName(path)
      const filename = getFileName(file)
      if (filename) {
        if (filename === componentName) {
          return componentName
        }
        return componentName ? `${filename}__${componentName}` : filename
      } else {
        return componentName
      }
    }
func_documentation_string: credit: https://github.com/styled-components/babel-plugin-styled-components/blob/37a13e9c21c52148ce6e403100df54c0b1561a88/src/visitors/displayNameAndId.js