How to use the @patternfly/patternfly/utilities/Accessibility/accessibility.css.visibleOnMd function in @patternfly/patternfly

const logoProps = {
      onClick: () => this.onTitleClick()
    };

    const gsUrl =
      'https://access.redhat.com/documentation/en-us/red_hat_managed_integration/1/html-single/getting_started/';
    const riUrl =
      'https://access.redhat.com/documentation/en-us/red_hat_managed_integration/1/html-single/release_notes/';
    const csUrl = 'https://access.redhat.com/support/';

    const MastheadToolbar = (
      
        
          
            
              <button aria-label="Settings">
                
              </button>

];
    const PageToolbar = (
      
        
          
            }
              isOpen={isHelpDropdownOpen}
              dropdownItems={helpDropdownItems}
            />
          
          
            {this.props.user}}
              dropdownItems={userDropdownItems}
            />
          
        
      
    );

    const Header = (

aria-label="Toggle Connect Form"
              variant={ButtonVariant.plain}
            >
              
            
          
          
             (this.notificationRef = el)}
              suppress={this.state.suppress}
            />
          
        
        
          
            
              {this.state.user}
            
             (this.dropdownRef = el)}
              handleContextHide={this.handleUserMenuHide}
              handleDropdownLogout={this.handleDropdownLogout}
              handleSuppress={this.handleSuppress}
              suppress={this.state.suppress}
              isConnected={this.isConnected}
              parentClass="user-button"
            />

const MastheadToolbar = (
      
        
          
            
              <button aria-label="Settings">
                
              </button>
            
            
              
                    
                  
                }
                autoFocus={false}
                dropdownItems={[